Remove opestack-common.conf
Remove opestack-common.conf

It's not used for anything. In fact, it made it look like it was used
but it is in fact, not.

Change-Id: Ia08b456805fd6acfe53773600c419d89ffb7ec5f

citrix-openstack-build/keystoneauth,jamielennox/keystoneauth,sileht/keystoneauth