Use the domain filter provided by keystoneclient

The keystone api client in horizon has it's own filter
by domain implementation for group listing. Switch
this over to use the keystoneclient domain filter for
a cleaner implementation.

Change-Id: Ie47b27ddc8bcaa9b9f22c5925580b8889a65c1d0
Closes-Bug: #1306213
Merge "Use the domain filter provided by keystoneclient"