FlowModResultEventTest is unstable.

FlowModResultEventTest failed on vtn-controller-integration Jenkins job.

java.lang.AssertionError: (FlowModResult)SUCCEEDED,(local)false expected:<1> but was:<0>
at org.junit.Assert.fail(Assert.java:91)
at org.junit.Assert.failNotEquals(Assert.java:645)
at org.junit.Assert.assertEquals(Assert.java:126)
at org.junit.Assert.assertEquals(Assert.java:470)
at org.opendaylight.vtn.manager.internal.TestUseVTNManagerBase.checkRegisteredFlowEntry(TestUseVTNManagerBase.java:1029)
at org.opendaylight.vtn.manager.internal.cluster.FlowModResultEventTest.testFlowModResultEvent(FlowModResultEventTest.java:183)

FlowModResultEventTest expects severe accuracy of timer task execution.
So it may fail if the build host is under heavy load.