Revert "Remove netcfg's unused options."

This reverts commit f8e83054cb8a8b13ee84a4aeeaa0a2fd8debca81.

Change-Id: Iede772f96ff9008277df433dcbb5f6603de65283
diff --git a/libnetutils/ifc_utils.c b/libnetutils/ifc_utils.c
index ab6c654..bfe7121 100644
--- a/libnetutils/ifc_utils.c
+++ b/libnetutils/ifc_utils.c
@@ -639,6 +639,26 @@
 #endif
 }
 
+/*
+ * Removes the default route for the named interface.
+ */
+int ifc_remove_default_route(const char *ifname)
+{
+    struct rtentry rt;
+    int result;
+
+    ifc_init();
+    memset(&rt, 0, sizeof(rt));
+    rt.rt_dev = (void *)ifname;
+    rt.rt_flags = RTF_UP|RTF_GATEWAY;
+    init_sockaddr_in(&rt.rt_dst, 0);
+    if ((result = ioctl(ifc_ctl_sock, SIOCDELRT, &rt)) < 0) {
+        ALOGD("failed to remove default route for %s: %s", ifname, strerror(errno));
+    }
+    ifc_close();
+    return result;
+}
+
 int
 ifc_configure(const char *ifname,
         in_addr_t address,