Fix intermittent test failures in PartitionedLeadersElectionScenarioTest
Seeing intermittent failures on jenkins, eg
Failed tests:
PartitionedLeadersElectionScenarioTest.runTest1:37->setupInitialMemberBehaviors:313->AbstractLeaderElectionScenarioTest.initializeLeaderBehavior:207
Missing messages of type class
org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply
Sometimes the initial AppendEntries messages go to dead letters,
probably b/c the follower actors haven't been fully created/initialized by akka.
So added retries as a workaround.
Change-Id: I5c838950f8ed2af3d5bc8ee3bd29602d8a8e8a9f
Signed-off-by: Tom Pantelis <tpanteli@brocade.com>