process: add ability to set a security label (v2)

v2: don't change a security label, if it isn't set.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
net: add a fast path for net_route_setup()

If routes are not set, we don't need to get information about links.

Signed-off-by: Andrey Vagin <avagin@openvz.org>