Cleanup: Remove unused "ipv6_local_address".

This was originally used on the "clat" interface. That interface is not created
anymore (since the switch to using a raw socket). Note that the v6 address used
on the raw socket is a combination of the plat subnet plus a host ID, and not
this link-local address.

Also fixup default values to match clatd.conf values.

Change-Id: I3470a02e6798b65cae0f8d7f074ce51fb0647e6a
diff --git a/config.h b/config.h
index fa47152..da7446e 100644
--- a/config.h
+++ b/config.h
@@ -21,14 +21,12 @@
 #include <netinet/in.h>
 #include <sys/system_properties.h>
 
-#define DEFAULT_IPV4_LOCAL_SUBNET "192.168.255.1"
-#define DEFAULT_IPV6_LOCAL_ADDRESS "fe80::c000:0004"
+#define DEFAULT_IPV4_LOCAL_SUBNET "192.0.0.4"
 
-#define DEFAULT_DNS64_DETECTION_HOSTNAME "ipv4.google.com"
+#define DEFAULT_DNS64_DETECTION_HOSTNAME "ipv4only.arpa"
 
 struct clat_config {
   int16_t mtu, ipv4mtu;
-  struct in6_addr ipv6_local_address;
   struct in6_addr ipv6_local_subnet;
   struct in6_addr ipv6_host_id;
   struct in_addr ipv4_local_subnet;