add security rules to qemu file for quantum

I am completely unsure if this is only required
when using qemu (or under what conditions it is required)

Change-Id: I5a2c737a9cdce0695e7029152bfbd3f8d04a53d9
refactor db deps

I really want to see all of these nasty deps
removes, but it will take some time to
understand why they are even there in the first
place.
Configure db_host

TODO - Daneyon, why exactly is this required?

Previously an option called db_host existed in
the db/mysql class, but it wasn't actually used.

This commit updates the databases created to
specify what host the db resides on.

This commit also adds some basic unit tests for
openstack::db::mysql.