complete upr -> dcp renaming

This renames mostly only stats

Change-Id: Ib2cf48190b2bf274f953b8da1b1cd1373de190c2
Reviewed-on: http://review.couchbase.org/40006
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>