MB-11728 Use provided seqnos for starting updater

When stale=false query is processed, we are performing
get_seqs() call multiple times. We can get the sequence numbers
only once and reuse multiple times and avoid extra latency.

Change-Id: Ia5de3717dbc95460fc3591f499f86287b05617d8
Reviewed-on: http://review.couchbase.org/39724
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: buildbot <build@couchbase.com>