Fix chaining of ObjCInterfaceDecl redeclarations

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146722 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index 2b7be7e..c95cf22 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -82,6 +82,7 @@
       ObjCInterfaceDecl *ProtocolDecl =
         ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(),
                                   &Context.Idents.get("Protocol"),
+                                  /*PrevDecl=*/0,
                                   SourceLocation(), true);
       Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl));
       PushOnScopeChains(ProtocolDecl, TUScope, false);