Add better routes for secondary DNS

We'd been doing no-gateway hostroutes for dns servers on secondary nets, but on
some devices (multi-homed stingray) this is a problem.  Add gateway-ed hostroutes
instead so the BP can do it's nonstandard "magical" demultiplexing.

bug:5011392
Change-Id: Ia48f69c8ddf2a37cfb8f014f078f96bf601d2ddb
2 files changed
tree: 80ef92dc6e0e26a0459f70d144cd0bea46812df2
  1. core/
  2. services/