CBD-926: Remove support for cyrus sasl

Change-Id: Ib6e03a8cfa9ce13d34790e94e39f9bd6719d2e4e
Reviewed-on: http://review.couchbase.org/25357
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>