Fix intermitent testFollowerResyncWith*LeaderRestart failure

Fix intermitent testFollowerResyncWith*LeaderRestart failure

NonVotingFollowerIntegrationTest#testFollowerResyncWithOneMoreLeaderLogEntryAfterNonPersistentLeaderRestart fails intermittently:

NonVotingFollowerIntegrationTest.testFollowerResyncWithOneMoreLeaderLogEntryAfterNonPersistentLeaderRestart:233 Did not receive message of type class org.opendaylight.controller.cluster.raft.base.messages.SnapshotComplete

This seems to be a side-effect of https://git.opendaylight.org/gerrit/#/c/62255/
which changes the timing a bit such that an install snapshot doesn't occur on the
follower which should happen in order to completely re-sycnc it with the leader -
instead it ends up removing the stale out-of-sync entries and appending the new ones
from the leader which gets the journal up-to-date but the stale entries had already
been applied to the state which leaves the state out-of-sync with journal. I added
an additional check in the follower to force the leader to install a snapshot
if the first out-of-sync log entry index <= the lastAppliedIndex which means the
entries to be removed have already been applied to the state.

Change-Id: Ic3815a694a8531d9f7f42f19ad8978d52fc902b3
Signed-off-by: Tom Pantelis <tompantelis@gmail.com>