Remove top-level using declaration from header files, as these aliases leak.

Reviewers: ilya-biryukov

Subscribers: arphaman, cfe-commits

Differential Revision: https://reviews.llvm.org/D53135

llvm-svn: 344337
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 16c7564..673d856 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -568,7 +568,7 @@
       auto &MM = ASTReader->getModuleManager();
       auto &PrimaryModule = MM.getPrimaryModule();
 
-      for (ModuleFile &MF : MM)
+      for (serialization::ModuleFile &MF : MM)
         if (&MF != &PrimaryModule)
           CI.getFrontendOpts().ModuleFiles.push_back(MF.FileName);