[NETNS]: Process interface address manipulation routines in the namespace.

The namespace is available when required except rtm_to_ifaddr. Add
namespace argument to it.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc net/ipv4/devinet.c
Simple merge