Remove unnecessary comments in base/files/file_util_win.cc

BUG=103737

Review-Url: https://codereview.chromium.org/2803563008
Cr-Commit-Position: refs/heads/master@{#463001}

base/files/file_util_win.cc

@@ -364,7 +364,6 @@ bool CreateTemporaryFileInDir(const FilePath& dir, FilePath* temp_file) {
     }
   }
 
-  // Exist early if we can't create an unique name.
   if (!create_file_success) {
     DPLOG(WARNING) << "Failed to get temporary file name in "
                    << UTF16ToUTF8(dir.value());