MB-17612 return NoAccessCreds if auth requires LDAP but LDAP is disabled
MB-17612 return NoAccessCreds if auth requires LDAP but LDAP is disabled

Change-Id: I020f97c49527e8394e93ad408110a71e296ae493
Reviewed-on: http://review.couchbase.org/59100
Tested-by: Artem Stemkovski <15a0730a27c69f62ab86f2b6c639fca202166c02@couchbase.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

couchbase/cbauth,couchbase/cbauth