When a bonding netdevice is admin-ed down it loses the slaves
attributes (set via ifenslave). This is not consistent with other
behavior of netdevices (example a qdisc attached to a netdevice doesnt
disappear or an attached IP address etc).
The included patch fixes this. Ive tested by ifenslaving, downing the
bond, checking /proc and making sure it still has the slaves, up-ing the
bond and making sure things continue to work.

Jay/Bonding folks if you are ok with it, just ACK it or include it in
your tree etc. Otherwise we can discuss.

Acked-by: Jay Vosburgh <fubar@us.ibm.com>

Signed-off-by: Jeff Garzik <jeff@garzik.org>