Error in action causes double execution

[jvalkeal]

New issue from #344 where exception in action with anonymous transition is executed twice.

This is in a middle ground if this should be considered a bug or a not-so-optimal behaviour as anonymous transition can be executed anytime. While it'd be nice that this could only happen once in a run-to-completion.

2017-05-11 18:22:06.061  WARN 20948 --- [nio-8380-exec-1] o.s.s.support.AbstractStateMachine       : Aborting as transition org.springframework.statemachine.transition.DefaultExternalTransition@31441b7e caused error java.lang.NullPointerException: Something was wrong
2017-05-11 18:22:06.062  WARN 20948 --- [nio-8380-exec-1] o.s.s.support.AbstractStateMachine       : Aborting as transition org.springframework.statemachine.transition.DefaultExternalTransition@31441b7e caused error java.lang.NullPointerException: Something was wrong