MB-100: removed dead sasl password validation code

Change-Id: I8b18943423be1d65bc3718d3e88bcc6da035cc7e
Reviewed-on: http://review.couchbase.org/28305
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Tested-by: Artem Stemkovski <artem@couchbase.com>