Hi,

I have an issue with a newly created Release JIRA Version step. It generates a null pointer exception if do not specify an option for Issues with status even though the description says that this is optional. A release jira step that i created a few months earlier does not have this issue.

```
ERROR - Step 'master>release jira version' is failed.
java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:191)
at com.google.common.base.Splitter.split(Splitter.java:383)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep.acceptedStatuses(ReleaseVersionStep.java:109)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep.onBeforeRelease(ReleaseVersionStep.java:128)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep$$EnhancerByCGLIB$$7e622f56.CGLIB$onBeforeRelease$7(<generated>)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep$$EnhancerByCGLIB$$7e622f56$$FastClassByCGLIB$$5afaaccc.invoke(<generated>)
at net.sf.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:215)
at com.pmease.quickbuild.DefaultScriptEngine$Interpolator.intercept(DefaultScriptEngine.java:273)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep$$EnhancerByCGLIB$$7e622f56.onBeforeRelease(<generated>)
at com.pmease.quickbuild.plugin.tracker.core.step.AbstractReleaseVersionStep.run(AbstractReleaseVersionStep.java:41)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep$$EnhancerByCGLIB$$7e622f56.CGLIB$run$12(<generated>)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep$$EnhancerByCGLIB$$7e622f56$$FastClassByCGLIB$$5afaaccc.invoke(<generated>)
at net.sf.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:215)
at com.pmease.quickbuild.DefaultScriptEngine$Interpolator.intercept(DefaultScriptEngine.java:273)
at com.pmease.quickbuild.plugin.tracker.jira.step.ReleaseVersionStep$$EnhancerByCGLIB$$7e622f56.run(<generated>)
at com.pmease.quickbuild.stepsupport.Step.execute(Step.java:539)
at com.pmease.quickbuild.stepsupport.StepExecutionJob.executeStepAwareJob(StepExecutionJob.java:30)
at com.pmease.quickbuild.stepsupport.StepAwareJob.executeBuildAwareJob(StepAwareJob.java:45)
at com.pmease.quickbuild.BuildAwareJob.execute(BuildAwareJob.java:60)
at com.pmease.quickbuild.grid.GridJob.run(GridJob.java:106)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
```