udevd: depend on netlink and remove all sequence reorder logic

udevd: depend on netlink and remove all sequence reorder logic

Netlink will never get out-of-order and we just depend on it from
now on. Udevsend messages will have no effect if they contain a
sequence number (SEQNUM).

Thanks to Bastian Blank <waldi@debian.org>, for the debugging session
which identified a bug where the timeouts are not working if
inotify was not available. All the timeout handling is removed
now and this issue should be solved.

Signed-off-by: Kay Sievers <kay.sievers@suse.de>