keep only the StringRef version of getFileOrSTDIN.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184826 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/FileUpdate/FileUpdate.cpp b/utils/FileUpdate/FileUpdate.cpp
index 9b48f94..6f9544f 100644
--- a/utils/FileUpdate/FileUpdate.cpp
+++ b/utils/FileUpdate/FileUpdate.cpp
@@ -45,7 +45,7 @@
 
   // Get the input data.
   OwningPtr<MemoryBuffer> In;
-  if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFilename.c_str(), In)) {
+  if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFilename, In)) {
     errs() << argv[0] << ": error: Unable to get input '"
            << InputFilename << "': " << ec.message() << '\n';
     return 1;