Ensure hostname resolves correctly

rabbitmq hangs on startup if the unqualified hostname for the
system doesn't resolve properly.  This change ensures that the
hostname is added to /etc/hosts so that will never happen with
devstack.

Change-Id: I2c250f38f9feb18d1a59f3a457c6d01c1d98499c
Handle more nicely when role root is already here

When using postgresql we were handling the fallback if the role root was
already here but this was still printing an error message, try to make
it a bit smarter.

Closes-Bug: #1265477
Change-Id: Ib3768dd182ab968e81038f900550f641b9a2af5c
Merge "Ensure hostname resolves correctly"
Merge branch 'master' of git://github.com/openstack-dev/devstack into opendaylight
Merge "Handle more nicely when role root is already here"
Merge branch 'master' of git://github.com/openstack-dev/devstack into opendaylight