Do not add default route during ifc_configure

Avoid duplicate default routes.
Remove adding of default routes during interface configuration as
route add/remove operation is managed by ConnectivityService via netd.
(cherry picked from commit 4a48635c72d91cf8decb7653948fe0c76de46098)

Change-Id: I982b95a44bf91d3850ca7752e307c1b1b6a66ecf