Remove fake_libvirt_utils from connection tests.
Remove fake_libvirt_utils from connection tests.

The fake implementation of libvirt.utils is confusing to debug
when things go wrong, direct mocks are clearer and keep everything
in one place.

Change-Id: Ief2c959d7c339e11b19e521de6e7d1be2f8722f8

mahak/nova,klmitch/nova,klmitch/nova,openstack/nova,rahulunair/nova,openstack/nova,rahulunair/nova,klmitch/nova,mahak/nova,klmitch/nova,mahak/nova,openstack/nova,rahulunair/nova