Add missing import to fakelibvirt.

This module calls time.sleep(1), but was not importing the time module.
This fixes it.

Fix bug 1133056.

Change-Id: Ifbba2a98ccdd8d5e26ce466831618ccab9e0b462

nova/tests/fakelibvirt.py

@@ -16,6 +16,7 @@
 
 from lxml import etree
 
+import time
 import uuid
 
 # Allow passing None to the various connect methods