A better version of r181699: use raw_string_ostream.str() instead of manually calling .flush().

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181702 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/Format.cpp

@@ -204,8 +204,7 @@ std::string configurationAsText(const FormatStyle &Style) {
   // reference here.
   FormatStyle NonConstStyle = Style;
   Output << NonConstStyle;
-  Stream.flush();
-  return Text;
+  return Stream.str();
 }
 
 // Returns the length of everything up to the first possible line break after