renamed upr -> dcp in module names

This is second (out of 3) phase of upr rename. This renames upr -> dcp
in module names.

Remaining code mentions of upr are all in stats.

Change-Id: Ie5b6cd84c223dca2f6d5c78b67509164034ce400
Reviewed-on: http://review.couchbase.org/39978
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>