Description of problem:
upgrading cluster version (3.2 -> 3.3) after RHEV-M (3.2 -> 3.3) upgrade throws error:
Error while executing action Edit Cluster properties: Internal Engine Error

and NPE in engine log (see additional info)

Version-Release number of selected component (if applicable):
Red Hat Enterprise Virtualization Manager Version: 3.3.0-0.23.master.el6ev 

How reproducible:
100%

Steps to Reproduce:
1. upgrade RHEVM from 3.2 to 3.3 (with RHEL host installed)
2. upgrade host to to have 3.3 compatible vdsm
3. upgrade cluster from 3.2 to 3.3

Actual results:
cannot upgrade cluster version, NPE appears

Expected results:
successful cluster upgrade

Additional info:
2013-09-24 16:38:30,454 ERROR [org.ovirt.engine.core.bll.UpdateVdsGroupCommand] (ajp-/127.0.0.1:8702-7) Command org.ovirt.engine.core.bll.UpdateVdsGroupCommand throw exception: java.lang.NullPointerException
	at org.ovirt.engine.core.bll.UpdateVdsGroupCommand.executeCommand(UpdateVdsGroupCommand.java:62) [bll.jar:]
	at org.ovirt.engine.core.bll.CommandBase.executeWithoutTransaction(CommandBase.java:1131) [bll.jar:]
	at org.ovirt.engine.core.bll.CommandBase.executeActionInTransactionScope(CommandBase.java:1216) [bll.jar:]
	at org.ovirt.engine.core.bll.CommandBase.runInTransaction(CommandBase.java:1892) [bll.jar:]
	at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInNewTransaction(TransactionSupport.java:210) [utils.jar:]
	at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInRequired(TransactionSupport.java:149) [utils.jar:]
	at org.ovirt.engine.core.utils.transaction.TransactionSupport.executeInScope(TransactionSupport.java:118) [utils.jar:]
	at org.ovirt.engine.core.bll.CommandBase.execute(CommandBase.java:1236) [bll.jar:]
	at org.ovirt.engine.core.bll.CommandBase.executeAction(CommandBase.java:366) [bll.jar:]
	at org.ovirt.engine.core.bll.Backend.runAction(Backend.java:416) [bll.jar:]
	at org.ovirt.engine.core.bll.Backend.runActionImpl(Backend.java:395) [bll.jar:]
	at org.ovirt.engine.core.bll.Backend.RunAction(Backend.java:353) [bll.jar:]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_40]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [rt.jar:1.7.0_40]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_40]
	at java.lang.reflect.Method.invoke(Method.java:606) [rt.jar:1.7.0_40]
	at org.jboss.as.ee.component.ManagedReferenceMethodInterceptorFactory$ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptorFactory.java:72) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:58) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:374) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.ovirt.engine.core.bll.interceptors.ThreadLocalSessionCleanerInterceptor.injectWebContextToThreadLocal(ThreadLocalSessionCleanerInterceptor.java:13) [bll.jar:]
	at sun.reflect.GeneratedMethodAccessor39.invoke(Unknown Source) [:1.7.0_40]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_40]
	at java.lang.reflect.Method.invoke(Method.java:606) [rt.jar:1.7.0_40]
	at org.jboss.as.ee.component.ManagedReferenceLifecycleMethodInterceptorFactory$ManagedReferenceLifecycleMethodInterceptor.processInvocation(ManagedReferenceLifecycleMethodInterceptorFactory.java:123) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:58) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.InitialInterceptor.processInvocation(InitialInterceptor.java:21) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:53) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ejb3.component.singleton.SingletonComponentInstanceAssociationInterceptor.processInvocation(SingletonComponentInstanceAssociationInterceptor.java:52) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInNoTx(CMTTxInterceptor.java:235) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.as.ejb3.tx.CMTTxInterceptor.supports(CMTTxInterceptor.java:374) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:218) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:64) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:59) [jboss-as-ejb3.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ee.component.TCCLInterceptor.processInvocation(TCCLInterceptor.java:45) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:165) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.as.ee.component.ViewDescription$1.processInvocation(ViewDescription.java:182) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation.jar:1.1.2.Final-redhat-1]
	at org.jboss.as.ee.component.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:72) [jboss-as-ee.jar:7.2.1.Final-redhat-10]
	at org.ovirt.engine.core.common.interfaces.BackendLocal$$$view10.RunAction(Unknown Source) [common.jar:]
	at org.ovirt.engine.ui.frontend.server.gwt.GenericApiGWTServiceImpl.RunAction(GenericApiGWTServiceImpl.java:131)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_40]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [rt.jar:1.7.0_40]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_40]
	at java.lang.reflect.Method.invoke(Method.java:606) [rt.jar:1.7.0_40]
	at com.google.gwt.rpc.server.RPC.invokeAndStreamResponse(RPC.java:196)
	at com.google.gwt.rpc.server.RpcServlet.processCall(RpcServlet.java:172)
	at com.google.gwt.rpc.server.RpcServlet.processPost(RpcServlet.java:233)
	at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:754) [jboss-servlet-api_3.0_spec.jar:1.0.2.Final-redhat-1]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [jboss-servlet-api_3.0_spec.jar:1.0.2.Final-redhat-1]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:295)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
	at org.ovirt.engine.ui.frontend.server.gwt.GwtCachingFilter.doFilter(GwtCachingFilter.java:132)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
	at org.ovirt.engine.core.utils.servlet.BrandingFilter.doFilter(BrandingFilter.java:65) [utils.jar:]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
	at org.ovirt.engine.core.utils.servlet.LocaleFilter.doFilter(LocaleFilter.java:64) [utils.jar:]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:246)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:149)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:499)
	at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:169)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:145)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:97)
	at org.jboss.web.rewrite.RewriteValve.invoke(RewriteValve.java:466)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:102)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:336)
	at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:488)
	at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:420)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:920)
	at java.lang.Thread.run(Thread.java:724) [rt.jar:1.7.0_40]

2013-09-24 16:38:30,461 ERROR [org.ovirt.engine.core.bll.UpdateVdsGroupCommand] (ajp-/127.0.0.1:8702-7) Transaction rolled-back for command: org.ovirt.engine.core.bll.UpdateVdsGroupCommand.
2013-09-24 16:38:30,465 INFO  [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (ajp-/127.0.0.1:8702-7) Correlation ID: 1c894cf0, Call Stack: null, Custom Event ID: -1, Message: Failed to update Host cluster (User: admin@internal)