11-dm-mpath.rules: dont't run "multipath -U" during coldplug

11-dm-mpath.rules: dont't run "multipath -U" during coldplug

When udevadm trigger is run after switching root, lots of simultaneous uevents
for both path and multipath devices arrive. In may happen that when "multipath
-U" is called on a dm device, the path's uevents haven't finished yet, thus
the paths aren't found in the udev db, and multipath -U erroneously concludes
that there are no usable paths. Avoid that by skipping "multipath -U" during
coldplug.

Fixes: "ce5ea6a 11-dm-mpath.rules: multipath -U for READY check"
Signed-off-by: Martin Wilck <mwilck@suse.com>