Use attribute from rabbitmq node to get rabbitmq IP address

The rabbitmq cookbook saves the IP address used by rabbitmq to listen,
so no need to do some fancy thing to get it.
Use helper from database cookbook to get database IP address

This way we're ready for when HA will be used for database.
Merge pull request #62 from vuntz/db-ha

Get ready for HA in database and rabbitmq
Cleanup neutron-server restart hack

We now delay all the neutron client command until the very end of the
chef-client run. This way we make sure the delayed neutron server restart
actions (triggered by template updates) are processed before the neutron client
commands run. This solution seems to be slightly less hackish.
Merge pull request #64 from rhafer/postinstall-cleanup

Cleanup neutron-server restart hack