pthreading: Monkeypatch threading module first

When using Python 2 we must monkey patch threading module before any
other module is imported. Next version of pthreading will raise if
monkey_patch() is called too late.

Change-Id: I49d327d0fd7c78edef62ecd43999651a475fee4d
Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/28738
Reviewed-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>