MB-9559 Don't collect expired items on replica vbuckets.

Expired items are identified on active vbuckets and replicated
to the replica vbuckets. Therefore, we don't need to collect the
list of expired items on replica vbuckets and push them into the
flusher queue. This will be also conflict with the UPR seqno
based replication.

Change-Id: Id888841ea0a44f23467fa666fb4b1252908f0f61
Reviewed-on: http://review.couchbase.org/30355
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>