Make security groups associated with Neutron port work

The security group names are now translated to UUIDs which is required
when using the python API. The lookup has been improved to find
existing security groups not part of the stack as well.

Fixes bug #1179481

Change-Id: I4f86bade87f89b867d12822c5f80aa5b075b7fbb
Merge "Make security groups associated with Neutron port work"