Fix another const bug in function.  Thanks to Daniel Krugler for finding this and the previous bug.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@113686 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/functional b/include/functional
index b9378aa..3cc21d4 100644
--- a/include/functional
+++ b/include/functional
@@ -1141,9 +1141,9 @@
 
     // deleted overloads close possible hole in the type system
     template<class _R2, class... _ArgTypes2>
-      bool operator==(const function<_R2(_ArgTypes2...)>&) = delete;
+      bool operator==(const function<_R2(_ArgTypes2...)>&) const = delete;
     template<class _R2, class... _ArgTypes2>
-      bool operator!=(const function<_R2(_ArgTypes2...)>&) = delete;
+      bool operator!=(const function<_R2(_ArgTypes2...)>&) const = delete;
 public:
     // function invocation:
     _R operator()(_ArgTypes...) const;