Modernize raw_fd_ostream's constructor a bit.

Take a StringRef instead of a "const char *".
Take a "std::error_code &" instead of a "std::string &" for error.

A create static method would be even better, but this patch is already a bit too
big.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216393 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/Timer.cpp

@@ -66,10 +66,10 @@ raw_ostream *llvm::CreateInfoOutputFile() {
   // each time -stats or -time-passes wants to print output to it. To
   // compensate for this, the test-suite Makefiles have code to delete the
   // info output file before running commands which write to it.
-  std::string Error;
-  raw_ostream *Result = new raw_fd_ostream(
-      OutputFilename.c_str(), Error, sys::fs::F_Append | sys::fs::F_Text);
-  if (Error.empty())
+  std::error_code EC;
+  raw_ostream *Result = new raw_fd_ostream(OutputFilename, EC,
+                                           sys::fs::F_Append | sys::fs::F_Text);
+  if (!EC)
     return Result;
   
   errs() << "Error opening info-output-file '"