Returning namedtuple from util.pidStat for simpler usage

Change-Id: I7cbac1c9175afbdecf42d40290026d518098e193
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/15024
Reviewed-by: Dan Kenigsberg <danken@redhat.com>