Create a specific helper for netlink kernel socket disposal. This just
let the code look better and provides a ground for proper disposal
inside a namespace.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Tested-by: NAlexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>