MB-8643: Remove registered tap client functionality

Change-Id: I510a96e46391bc684d6320853392c972a45d0217
Reviewed-on: http://review.couchbase.org/27336
Reviewed-by: Chiyoung Seo <chiyoung.seo@gmail.com>
Tested-by: Chiyoung Seo <chiyoung.seo@gmail.com>