Removing unused "2.5.2" manifests

Change-Id: Ie84da4a6f0cb0a8319c8278132c1792e4f97de1a
Reviewed-on: http://review.couchbase.org/42197
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>