Use a valid hostname to connect to MongoDB

After having changed the bind address of the MongoDB server the client
can't connect using the default host value (localhost). Use the
controller hostname instead of localhost to connect and create/setup the
ceilometer database.

Change-Id: If1a43889fdbe7bf0872ed8be07a111df4bc02714
backport: havana
(cherry picked from commit afeae26e722e93fd05a5ccdacd536d9258453016)