Use sys::fs::createTemporaryFile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185719 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/GraphWriter.cpp b/lib/Support/GraphWriter.cpp
index 20214c7..64d2164 100644
--- a/lib/Support/GraphWriter.cpp
+++ b/lib/Support/GraphWriter.cpp
@@ -68,8 +68,7 @@
 std::string llvm::createGraphFilename(const Twine &Name, int &FD) {
   FD = -1;
   SmallString<128> Filename;
-  error_code EC = sys::fs::unique_file(Twine(Name) + "-%%%%%%%.dot",
-                                       FD, Filename);
+  error_code EC = sys::fs::createTemporaryFile(Name, "dot", FD, Filename);
   if (EC) {
     errs() << "Error: " << EC.message() << "\n";
     return "";