DPORwHeuristics + Non-determinsm causes unexpected paths

[colin-scott]

This is to be expected, but if the application exhibits non-determinism, DPOR sometimes crashes with:

[ERROR] [03/15/2015 00:16:03.718] [new-system-5-akka.actor.default-dispatcher-9] [akka://new-system-5/user/raft-member-3] Unexpected path
java.lang.Exception: Unexpected path
        at akka.dispatch.verification.DPORwHeuristics.setParentEvent(DPORwHeuristics.scala:170)
        at akka.dispatch.verification.DPORwHeuristics.schedule_new_message(DPORwHeuristics.scala:446)
        at akka.dispatch.verification.Instrumenter.afterMessageReceive(Instrumenter.scala:263)
        at sample.WeaveActor.ajc$after$sample_WeaveActor$3$79e3ab71(WeaveActor.aj:53)
        at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516)
        at akka.actor.ActorCell.invoke(ActorCell.scala:487)
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238)
        at akka.dispatch.Mailbox.run(Mailbox.scala:220)
        at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393)
        at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
        at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
        at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
        at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
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Not sure if we should necessarily crash or not