MB-12274: Update manifest for final dev branches.

This manifest is the same as released/2.5.1.xml, except for the
projects ep-engine, memcached, ns_server, and couchdb, which are
pointing to specific cherry-pick fix branches.

Change-Id: Ia075bdcfa7c0abbdac747308b55e23c63361c221
Reviewed-on: http://review.couchbase.org/43334
Tested-by: Chris Hillery <ceej@couchbase.com>
Reviewed-by: Patrick Varley <patrick@couchbase.com>