MB-7790: Always use 127.0.0.1 instead of localhost

127.0.0.1 doesn't need to be resolved and will be more resilient
to resolver misconfigurations on a server such as accidentally
removing locahost from /etc/hosts.

Change-Id: Ie26ba81b507406687def992ce196b797161df792
Reviewed-on: http://review.couchbase.org/25407
Reviewed-by: Chiyoung Seo <chiyoung.seo@gmail.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>