Always try to set/remove default routes

Must clean up default route if a default 3g connection is replaced
by a non-default (ie, mms) connection on the same interface.

Also stop mucking with all connections dns and routes - do it only
for the connection that has changed.

bug:2865974
Change-Id: I589a0b2768b5e67b608fde181e7ddbd7fce4f491
1 file changed
tree: fb533cc4c5523da4245ec1307be76807d3583403
  1. core/
  2. services/