Remove unused private member variables uncovered by the recent changes to clang's -Wunused-private-field.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160583 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/YAMLParser.cpp

@@ -489,9 +489,6 @@ private:
   /// @brief Can the next token be the start of a simple key?
   bool IsSimpleKeyAllowed;
 
-  /// @brief Is the next token required to start a simple key?
-  bool IsSimpleKeyRequired;
-
   /// @brief True if an error has occurred.
   bool Failed;
 
@@ -704,7 +701,6 @@ Scanner::Scanner(StringRef Input, SourceMgr &sm)
   , FlowLevel(0)
   , IsStartOfStream(true)
   , IsSimpleKeyAllowed(true)
-  , IsSimpleKeyRequired(false)
   , Failed(false) {
   InputBuffer = MemoryBuffer::getMemBuffer(Input, "YAML");
   SM.AddNewSourceBuffer(InputBuffer, SMLoc());