Delete dummy couch kvstore

Change-Id: If9103e8699b60ec4ec3fdd136eed4bcd7c1d5612
Reviewed-on: http://review.couchbase.org/29981
Reviewed-by: David Liao <david.liao@couchbase.com>
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>