shill: Delete existing routes when the device is started.

BUG=chromium-os:27358
TEST=Unit tests, network_WiFiManager, manually add foreign routes and
ensure they are deleted, also test to make sure default route remains
after DHCP renewal

Change-Id: Ic26b70d685491f31699ff4684ed289e76af8a9ca
Reviewed-on: https://gerrit.chromium.org/gerrit/17640
Commit-Ready: Thieu Le <thieule@chromium.org>
Reviewed-by: Thieu Le <thieule@chromium.org>
Tested-by: Thieu Le <thieule@chromium.org>
diff --git a/connection_unittest.cc b/connection_unittest.cc
index 16e0f78..08d85b9 100644
--- a/connection_unittest.cc
+++ b/connection_unittest.cc
@@ -198,14 +198,14 @@
     connection->ReleaseRouting();
 
     // The destructor will remove the routes and addresses.
-    EXPECT_CALL(routing_table_, FlushRoutes(kTestDeviceInterfaceIndex0, true));
+    EXPECT_CALL(routing_table_, FlushRoutes(kTestDeviceInterfaceIndex0));
     EXPECT_CALL(*device_info_.get(),
                 FlushAddresses(kTestDeviceInterfaceIndex0));
   }
 }
 
 TEST_F(ConnectionTest, Destructor) {
-  EXPECT_CALL(routing_table_, FlushRoutes(kTestDeviceInterfaceIndex1, true));
+  EXPECT_CALL(routing_table_, FlushRoutes(kTestDeviceInterfaceIndex1));
   EXPECT_CALL(*device_info_, FlushAddresses(kTestDeviceInterfaceIndex1));
   {
     ConnectionRefPtr connection(new Connection(kTestDeviceInterfaceIndex1,