MB-7543 Rev sequence number shouldn't be set to zero.

We should make sure that the revision sequence number shouldn't
be zero during warmup or when we receive tap_deletion,
tap_mutation, set_with_meta, and delete_with_meta.

Change-Id: I4316e0b688e2f29efc94533fab6fe61df0ea871a
Reviewed-on: http://review.couchbase.org/24004
Reviewed-by: Jin Lim <jin@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung.seo@gmail.com>
Reviewed-on: http://review.couchbase.org/24007
Reviewed-by: Chiyoung Seo <chiyoung.seo@gmail.com>