Updated openstack/openstack
Project: openstack/nova  372e2aac7f1eb705900d8d095fdd3a24d5d2420b

Clear libvirt test on LibvirtDriverTestCase

We already create a class variable for connection,
no need to create each one for every test cases.

Change-Id: I635f5993888b21dc9b497e588057af5f794f55b3