Make the default constructor of IdentifierResolver::iterator public.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@54264 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/IdentifierResolver.h b/lib/Sema/IdentifierResolver.h
index 2949042..8ccd5fe 100644
--- a/lib/Sema/IdentifierResolver.h
+++ b/lib/Sema/IdentifierResolver.h
@@ -188,7 +188,6 @@
     uintptr_t Ptr;
     typedef IdDeclInfo::DeclsTy::iterator BaseIter;
 
-    iterator() : Ptr(0) {}
     /// A single NamedDecl. (Ptr & 0x1 == 0)
     iterator(NamedDecl *D) {
       Ptr = reinterpret_cast<uintptr_t>(D);
@@ -216,6 +215,8 @@
     
     friend class IdentifierResolver;
   public:
+    iterator() : Ptr(0) {}
+
     NamedDecl *operator*() const {
       if (isIterator())
         return *getIterator();