Description of problem:
Registering a Template will cause an NPE since the init function of ImportVmTemplateFromConfigurationCommand executes updateMaxMemorySize which uses getVmTemplate().
Since unregistered entities does not exist in the vm_static table getVmTemplate() returns null.

This is probably related to the change introduced in https://gerrit.ovirt.org/#/c/67747/

2017-02-05 15:51:26,601+02 ERROR [org.ovirt.engine.core.bll.CommandsFactory] (default task-46) [d1ab8f8b-98d0-4d5f-8282-ec88677fcb32] An exception has occurred while trying to create a comma
nd object for command 'ImportVmTemplateFromConfiguration' with parameters 'ImportVmTemplateParameters:{commandId='824772de-3d01-45ae-b530-5c5c6fa0e8b1', user='null', commandType='Unknown'}':
 WELD-000049: Unable to invoke protected final void org.ovirt.engine.core.bll.CommandBase.postConstruct() on org.ovirt.engine.core.bll.exportimport.ImportVmTemplateFromConfigurationCommand@2
b8292ad
2017-02-05 15:51:26,611+02 ERROR [org.ovirt.engine.api.restapi.resource.AbstractBackendResource] (default task-46) [] Operation Failed: java.lang.NullPointerException
2017-02-05 15:51:26,611+02 ERROR [org.ovirt.engine.api.restapi.resource.AbstractBackendResource] (default task-46) [] Exception: javax.ejb.EJBException: java.lang.NullPointerException
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInNoTx(CMTTxInterceptor.java:213) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInNoTx(CMTTxInterceptor.java:265) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.supports(CMTTxInterceptor.java:374) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:243) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.F
inal]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.as.ejb3.component.invocationmetrics.WaitTimeInterceptor.processInvocation(WaitTimeInterceptor.java:47) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.as.ejb3.security.SecurityContextInterceptor.processInvocation(SecurityContextInterceptor.java:100) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.as.ejb3.deployment.processors.StartupAwaitInterceptor.processInvocation(StartupAwaitInterceptor.java:22) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:64) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:67) [wildfly-ejb3-10.1.0.Final.jar:10.1.0.Final]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.invocation.ContextClassLoaderInterceptor.processInvocation(ContextClassLoaderInterceptor.java:64)
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
        at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)

Version-Release number of selected component (if applicable):

How reproducible:
100%

Steps to Reproduce:
Make sure you have an active DC with multiple storage domains.
1. Create a VM with one disk on a storage domain
2. Create a Template from that VM
3. Move the Storage Domain to maintenance and detach it from the DC
4. Attach the Storage Domain back again and activate it
5. Try to register the Template to the engine using the following REST command:

POST /api/storagedomains/xxxxxxx-xxxx-xxxx-xxxxxx/templates/xxxxxxx-xxxx-xxxx-xxxxxx/register HTTP/1.1
Accept: application/xml
Content-type: application/xml

<action>
    <cluster id='bf5a9e9e-5b52-4b0d-aeba-4ee4493f1072'></cluster>
</action>

Actual results:

NPE

<action>
    <allow_partial_import>true</allow_partial_import>
    <cluster id="a205d3ea-e61c-4d0e-ad55-daaf4ab7f782"/>
    <fault>
        <detail>java.lang.NullPointerException</detail>
        <reason>Operation Failed</reason>
    </fault>
    <status>failed</status>
</action>


Expected results:
The registration should succeed

Additional info: