MB-27833: Use maybe_add_brackets in rest_url...
MB-27833: Use maybe_add_brackets in rest_url...

...API in menelaus_rest module to handle IPv6 addresses.

In the join_cluster path the construction of addNodeV2 REST API was
not being done correctly if raw IPv6 addresses were being used. The
fix here is to add the usage of maybe_add_brackets into rest_url
API from menelaus_rest module which is the one that constructs the
URL.

Change-Id: Icb8185bcce1946946c7ffa82da18858bf8336401
Reviewed-on: http://review.couchbase.org/88671
Well-Formed: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Tested-by: Ajit Yagaty <670a5cadfa9668cb910cc315f6527868cd5ab42a@couchbase.com>
Reviewed-by: Timofey Barmin <f30bdb2be8598fcffd705a378b25da4842d6bd7b@couchbase.com>

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