libiptc symbols clash (Phil Oester <kernel@linuxace.com>)

As reported by Dmitry Levin, the TC_NUM_RULES and TC_GET_RULE exports
clash.  His patch below, resolving bug #456
diff --git a/libiptc/libip6tc.c b/libiptc/libip6tc.c
index 8ca5ea6..5b3ae0b 100644
--- a/libiptc/libip6tc.c
+++ b/libiptc/libip6tc.c
@@ -89,6 +89,8 @@
 #define TC_FREE			ip6tc_free
 #define TC_COMMIT		ip6tc_commit
 #define TC_STRERROR		ip6tc_strerror
+#define TC_NUM_RULES		ip6tc_num_rules
+#define TC_GET_RULE		ip6tc_get_rule
 
 #define TC_AF			AF_INET6
 #define TC_IPPROTO		IPPROTO_IPV6