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/build.json b/build.json
index c395f10..550f3af 100644
--- a/build.json
+++ b/build.json
@@ -271,7 +271,7 @@
       "vs_project_guid": "{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}",
       "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",