This fixes a bug where netpoll can dereference a null ifa_list pointer when
not supplied an IP address at module load and the interface is up but no IP
is configured.

Bonus: unrelated netif_running cleanup

Signed-off by: Jeff Moyer <jmoyer@redhat.com>
Signed-off by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>