Remove unused private field to suppress a build warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174491 91177308-0d34-0410-b5e6-96231b3b80d8

Author: topperc

lib/IR/AttributeImpl.h

@@ -101,7 +101,6 @@ class StringAttributeEntry : public AttributeEntry {
 /// could be a single enum, a tuple, or a string.
 class AttributeImpl : public FoldingSetNode {
   LLVMContext &Context;  ///< Global context for uniquing objects
-  Constant *Kind;        ///< Kind of attribute: enum or string
 
   AttributeEntry *Entry; ///< Holds the kind and value of the attribute