python3: Switch to mox3 instead of mox

In order to transition to a python 3.x compatible world,
lets switch to mox3 which is python 3.x compatible drop-in
replacement of mox.

Change-Id: Id971475f0e92900689d6784ffc55ae5fe63d9fe4

test-requirements.txt

@@ -2,7 +2,7 @@ hacking>=0.8.0,<0.9
 
 coverage>=3.6
 discover
-mox>=0.5.3
+mox3>=0.7.0
 mock>=1.0
 sphinx>=1.1.2,<1.2
 testrepository>=0.0.17

tests/test_http.py

@@ -17,7 +17,7 @@ import errno
 import socket
 import urlparse
 
-import mox
+from mox3 import mox
 import six
 import testtools