Revert "bonding: remove sysfs before removing devices"

This reverts commit 4de79c73.

This patch introduces a new bug which causes access to freed memory.
In bond_uninit: list_del(&bond->bond_list);
bond_list is linked in bond_net's dev_list which is freed by
unregister_pernet_subsys.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>