[libclang] Fix a test and a warning on windows.

Patch by Guy Benyei!

llvm-svn: 176806
diff --git a/clang/tools/c-index-test/c-index-test.c b/clang/tools/c-index-test/c-index-test.c
index b749bf5..46d61e9 100644
--- a/clang/tools/c-index-test/c-index-test.c
+++ b/clang/tools/c-index-test/c-index-test.c
@@ -2223,7 +2223,7 @@
   PrintDiagnostics(TU);
   clang_disposeTranslationUnit(TU);
   clang_disposeIndex(CIdx);
-  free(Filenames);
+  free((void *)Filenames);
   free_remapped_files(unsaved_files, num_unsaved_files);
   return 0;
 }