MB-11908: log successful shutdown
MB-11908: log successful shutdown

I.e. there is now info message like that:

[ns_server:info,2015-01-08T15:45:51.575,n_0@127.0.0.1:<0.2.0>:ns_bootstrap:stop:51]Successfully stopped ns_server

in case of successful shutdown

Change-Id: I19c2278ac67bd5113bcc294ef669fe9c4c1f06e4
Reviewed-on: http://review.couchbase.org/45118
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

mschoch/ns_server,ceejatec/ns_server,nimishzynga/ns_server,ceejatec/ns_server,membase/ns_server,ceejatec/ns_server,mschoch/ns_server,ceejatec/ns_server,membase/ns_server,nimishzynga/ns_server,membase/ns_server,nimishzynga/ns_server,membase/ns_server,mschoch/ns_server,ceejatec/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,mschoch/ns_server,membase/ns_server,ceejatec/ns_server,membase/ns_server,mschoch/ns_server,nimishzynga/ns_server,mschoch/ns_server