name rabbitmq nodes with short hostnames (bz1119429)

RabbitMQ node names must be short names, not fqdn.  For example,
'node1.example.org' is invalid, but 'node1' is valid.  This strips off
the domain part of the hostname when creating the cluster node names.
BZ #1118067 - Intermittent incompletion of puppet run on compute nodes.

https://bugzilla.redhat.com/show_bug.cgi?id=1118067

It seems that ceilometer::compute depends on a nova user group existing, which
may or may not have been created yet with the existing code.  Add an ordering
dependency to make sure nova is installed and configured first.  Thanks @jayg
for helping debug.
Merge pull request #316 from cwolferh/bz1118067

BZ #1118067 - Intermittent incompletion of puppet run on compute nodes.
Merge pull request #313 from jeckersb/rabbit_short_node_names

name rabbitmq nodes with short hostnames (bz1119429)