Description of problem:
Adding/modifying variables of kickstartable distributions leads to ISE.

Version-Release number of selected component (if applicable):
SW nightly
spacewalk-java-2.1.76-1.fc19.noarch

How reproducible:
always

Steps to Reproduce:
1. in WebUI: System -> Kickstart -> Distributions -> <ks-tree> -> Variables
2. ISE

Actual results:

2013-11-19 10:21:23,963 [ajp-bio-0:0:0:0:0:0:0:1-8009-exec-15] WARN  org.apache.struts.action.RequestProcessor - Unhandled Exception thrown: class java.lang.NullPointerException
2013-11-19 10:21:23,966 [ajp-bio-0:0:0:0:0:0:0:1-8009-exec-15] ERROR com.redhat.rhn.frontend.servlets.SessionFilter - Error during transaction. Rolling back
javax.servlet.ServletException: java.lang.NullPointerException
	at org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:520)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:427)
	at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
	at com.redhat.rhn.frontend.struts.RhnRequestProcessor.process(RhnRequestProcessor.java:102)
	at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
	at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.redhat.rhn.frontend.servlets.AuthFilter.doFilter(AuthFilter.java:127)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)
	at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.redhat.rhn.frontend.servlets.LocalizedEnvironmentFilter.doFilter(LocalizedEnvironmentFilter.java:67)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.redhat.rhn.frontend.servlets.EnvironmentFilter.doFilter(EnvironmentFilter.java:100)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.redhat.rhn.frontend.servlets.SessionFilter.doFilter(SessionFilter.java:57)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at com.redhat.rhn.frontend.servlets.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:97)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:200)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.NullPointerException
	at com.redhat.rhn.frontend.action.kickstart.KickstartVariableAction.setupFormValues(KickstartVariableAction.java:105)
	at com.redhat.rhn.frontend.action.kickstart.KickstartVariableAction.execute(KickstartVariableAction.java:71)
	at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
	... 41 more


Expected results:
no ISE, variables can be added/modified