Let getIdentifierNamespaceForKind know about aliases and have it treat them just like namespace decls.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67963 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclBase.cpp b/lib/AST/DeclBase.cpp
index 634c86e..bc7ac56 100644
--- a/lib/AST/DeclBase.cpp
+++ b/lib/AST/DeclBase.cpp
@@ -190,6 +190,7 @@
     case FunctionTemplate:
     case ClassTemplate:
     case TemplateTemplateParm:
+    case NamespaceAlias:
       return IDNS_Tag | IDNS_Ordinary;
     
     // Never have names.