Provides support for Neutron DB Configuration in Havana

Do NOT Merge until the following upstream patch is accepted:

  https://review.openstack.org/#/c/54790/

Previously, the database configuration was contained in the
plugin.ini.  This patch allows the hiera model to configure
the db settings in neutron.conf instead of the plugin.ini's.
Merge pull request #215 from CiscoSystems/neutron_db

Provides support for Neutron DB Configuration in Havana