Add a default variable plugin

As it stands right now, there are a number of scenarios where we would
like to be more DRY. We have multiple environments that we support and
copying and pasting variables from one environment to the next is a
recipe for disaster. Therefore provide an optional group_vars wrapper
plugin.
pep8 improvements

Fix all pep8 failures for the default_vars plugin.
Add vars_plugin declaration to ansible.cfg

With the introduction of a default_vars plugin, add its path to the
ansible configuration. This will enable this functionality, if a
defaults file is configured, else it will behave as it always has.
Merge pull request #224 from craigtracey/varsplugin

Add a default variable plugin
Upgrade neutron to allow multiple api processes.

Upgrade neutron to pick up a recent backport to havana,
which allows running multiple neutron-server worker
processes.

This is desirable, because clients have been observed
to timeout talking to neutron-server when several requests
are sent in close succession.
Merge pull request #226 from blueboxgroup/neutron-api-workers

Upgrade neutron to allow multiple api processes.
Specify internal ip for iscsi.
Update haproxy version.

The previous version has been removed from the PPA.
adding pecona backups
set pecona backup to run on primary db
Merge pull request #227 from blueboxgroup/percona-backup

adding percona backups
Fix syntax error in percona backup.
Add library for attaching ovs ports to bridges.