Moving python_sitearch to python_sitelib

VDSM uses pure python code, therefore there is no need to use
specific sitearch at all while installation vdsm-python files

Change-Id: I4476626aec2e2754ab0942ad163292672ea48bd0
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1141669
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/33711
Reviewed-by: Dan Kenigsberg <danken@redhat.com>