Checking for the link status seems to be broken with the current snapshot. python -c 'import dbus; b = dbus.SystemBus(); o = b.get_object("org.freedesktop.NetworkManager", "/org/freedesktop/NetworkManager"); print o.state()' returns None rather than the enums from previously. This ends up breaking online status checking of, eg, yum-updatesd.
fixed in NM svn r2865