allow "special" auth for any endpoints

This special auth is going to be used by cbauth

Change-Id: Ic69fb3715bcb3fcd328150535460c8951a3edcc0
Reviewed-on: http://review.couchbase.org/43657
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>