Add an ActOnNamespaceAliasDef action and have the parser call it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67915 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 229c181..121bf04 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -124,7 +124,8 @@
   ExpectAndConsume(tok::semi, diag::err_expected_semi_after,
                    "namespace name", tok::semi);
   
-  return 0;
+  return Actions.ActOnNamespaceAliasDef(CurScope, AliasLoc, Alias, SS,
+                                        NamespaceLoc, NamespaceName);
 }
 
 /// ParseLinkage - We know that the current token is a string_literal