Use new-style UID routing.

Kernel prebuilts for OC devices have been updated, so the legacy
attributes are not being used. Use the new attributes only. This
will ensure that devices aren't using the old code by mistake, as
any such devices will fail the VPN CTS tests.

Test: will be tested while treehugger runs.
Bug: 16355602
Change-Id: I068d1f42a5e45507ef5324d024201743304f3f43