Rename all classes/variables with upr to dcp

Change-Id: Iaf644f5034fdb30a14c400ec55def22d8bb0ba87
Reviewed-on: http://review.couchbase.org/40942
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Reviewed-by: Sundararaman Sridharan <sundar@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>