MB-11361: Make upr no-ops optional

Clients that are both on localhost do not need to use no-ops and
can choose not to turn this feature on for their connection.

Change-Id: I0d1186461e3aee5efde05cce0472f64655a809ab
Reviewed-on: http://review.couchbase.org/38991
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>
Move flow control logic into its own function

Change-Id: Iab3e1afdee4666ff3ea07cdda06445d1f9933df3
Reviewed-on: http://review.couchbase.org/39176
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>