Fix ipv6.c build breakage on Windows.
	Change on 2014/12/11 by jtattermusch <jtattermusch@google.com>
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=81910401
diff --git a/Makefile b/Makefile
index 095e0aa..6bc8f03 100644
--- a/Makefile
+++ b/Makefile
@@ -750,7 +750,7 @@
 
 LIBGRPC_TEST_UTIL_SRC = \
     test/core/util/grpc_profiler.c \
-    test/core/util/ipv6.c \
+    test/core/util/ipv6_posix.c \
     test/core/util/parse_hexstring.c \
     test/core/util/port_posix.c \
     test/core/util/slice_splitter.c \