Only ns_server needs clean-dfxq

Change-Id: If63a0d276f92b8d452ca9f15e1f9c968d6b35840
Reviewed-on: http://review.couchbase.org/43669
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>
Reviewed-by: Volker Mische <volker.mische@gmail.com>