Use sys::fs::createTemporaryFile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185719 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/lto/LTOCodeGenerator.cpp b/tools/lto/LTOCodeGenerator.cpp
index 88f2a0f..022a04c 100644
--- a/tools/lto/LTOCodeGenerator.cpp
+++ b/tools/lto/LTOCodeGenerator.cpp
@@ -162,8 +162,7 @@
   // make unique temp .o file to put generated object file
   SmallString<128> Filename;
   int FD;
-  error_code EC = sys::fs::unique_file("lto-llvm-%%%%%%%.o",
-                                       FD, Filename);
+  error_code EC = sys::fs::createTemporaryFile("lto-llvm", "o", FD, Filename);
   if (EC) {
     errMsg = EC.message();
     return true;