MB-100: speed up menelaus_auth:check_auth
MB-100: speed up menelaus_auth:check_auth

I.e. via 'latest-config-marker' api.

Change-Id: I0bd2794e6b703035495115f6eaef4c7c93040481
Reviewed-on: http://review.couchbase.org/27581
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

vzasade/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,nimishzynga/ns_server,mschoch/ns_server,nimishzynga/ns_server,mschoch/ns_server,membase/ns_server,membase/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,membase/ns_server,daverigby/ns_server,membase/ns_server,ceejatec/ns_server,membase/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,membase/ns_server,ceejatec/ns_server,vzasade/ns_server,nimishzynga/ns_server,daverigby/ns_server,vzasade/ns_server,daverigby/ns_server,nimishzynga/ns_server,mschoch/ns_server,ceejatec/ns_server,nimishzynga/ns_server,ceejatec/ns_server,mschoch/ns_server,mschoch/ns_server,daverigby/ns_server,mschoch/ns_server,ceejatec/ns_server,vzasade/ns_server,daverigby/ns_server