crash /uilogin handler if LDAP is misconfigured
crash /uilogin handler if LDAP is misconfigured

…so this api behaves consistently with other REST api's -
returns 500

Change-Id: I86abb4171cb1f6ecf05677f573b5f85893731233
Reviewed-on: http://review.couchbase.org/60453
Tested-by: Artem Stemkovski <15a0730a27c69f62ab86f2b6c639fca202166c02@couchbase.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

membase/ns_server,membase/ns_server,ceejatec/ns_server,ceejatec/ns_server,ceejatec/ns_server,ceejatec/ns_server,ceejatec/ns_server,ceejatec/ns_server,membase/ns_server,membase/ns_server,membase/ns_server,membase/ns_server