net: Implement routes conversion

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
net: Zap routes for a while

There are devices such as "venet" which are
not yet covered, and thus restore on vanilla
kernel get broken.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>