Bug 4850: Fix follower out-of-sync logic wrt replicatedToAllIndex

Bug 4850: Fix follower out-of-sync logic wrt replicatedToAllIndex

If the AppendEntries prevLogIndex is -1 and replicatedToAllIndex != -1,
it flags the follower as out-of-sync if there's no log entry for
replicatedToAllIndex. However replicatedToAllIndex may be in the
snapshot so I added a check for that as well. This fixes the issue
described in bug 4850.

Change-Id: If499dadc5f2a3c3823d617e60410b0f63df389d7
Signed-off-by: Tom Pantelis <tpanteli@brocade.com>
(cherry picked from commit bb817d2b20a252f3acde329cba6ce98c592cd847)