CCBC-488: Fix incorrect bounds check in lcbvb_vbreplica

Change-Id: I0b57c4c806db2fa24dbbee53970920421312791d
Reviewed-on: http://review.couchbase.org/40082
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>