Let using directives refer to namespace aliases. Fixes PR5479.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89657 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/DeclPrinter.cpp b/lib/AST/DeclPrinter.cpp
index 864f114..24d3da4 100644
--- a/lib/AST/DeclPrinter.cpp
+++ b/lib/AST/DeclPrinter.cpp
@@ -505,7 +505,7 @@
   Out << "using namespace ";
   if (D->getQualifier())
     D->getQualifier()->print(Out, Policy);
-  Out << D->getNominatedNamespace()->getNameAsString();
+  Out << D->getNominatedNamespaceAsWritten()->getNameAsString();
 }
 
 void DeclPrinter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {