Use netlink to add/delete rules as well as routes.

Use netlink to add/delete rules as well as routes.

Also change the indentation of the rtattrs used in modifyIpRoute
to make it easier to see what attributes are being used and in
what sequence.

This change does not yet pass the errors back to CommandListener;
that is done in the next change in the series.

Change-Id: Ib2e174386c63cb0647d838d9c7d731cd6df39c4f