CBD-926: Remove support for linking in default_engine

Change-Id: Ia81c45708a1472c235d4693e6fd8aeb162c86859
Reviewed-on: http://review.couchbase.org/25365
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>