MB-10059 Set a backfilled QueuedItem's rev_seq from hashtable.

Change-Id: Idfd3eb5a69147c657705232b2c0b6cf0a38ab902
Reviewed-on: http://review.couchbase.org/33503
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>