Removing LLVM_DELETED_FUNCTION, as MSVC 2012 was the last reason for requiring the macro. NFC; LLVM edition.

llvm-svn: 229340

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -350,7 +350,7 @@ namespace {
   /// @brief A class for maintaining the slot number definition
   /// as a placeholder for the actual definition for forward constants defs.
   class ConstantPlaceHolder : public ConstantExpr {
-    void operator=(const ConstantPlaceHolder &) LLVM_DELETED_FUNCTION;
+    void operator=(const ConstantPlaceHolder &) = delete;
   public:
     // allocate space for exactly one operand
     void *operator new(size_t s) {