BUG 2185 : Follower should request forceInstallSnapshot in out-of-sync scenario

BUG 2185 : Follower should request forceInstallSnapshot in out-of-sync scenario

When the Follower detects that it has more entries in it's log than the Leader
it might be an indication that the Follower was previously a Leader and therefore
it has additional entries in it's log which are missing in the Leader. When the
RaftPolicy is set to allow commits before consensus this could also mean that the
state now has more data than should be present in there. In this scenario Follower
requests the Leader to InstallSnapshot.

Change-Id: I517af148c3933f798ceb87ff88c77c396590881f
Signed-off-by: Moiz Raja <moraja@cisco.com>