Lock ForestDB in Sherlock to current stable rev

Change-Id: I92fafd693d412229e20aa553669aaaa7409cfd4e
Reviewed-on: http://review.couchbase.org/44157
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>