Separate the serialization library's diagnostics from the frontend's
diagnostics. Conflating them was highly confusing and makes it harder to
establish a firm layering separation between these two libraries.

llvm-svn: 146207
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 236c2bd..27dda85 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -14,9 +14,9 @@
 #include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/ASTDeserializationListener.h"
 #include "clang/Serialization/ModuleManager.h"
+#include "clang/Serialization/SerializationDiagnostic.h"
 #include "ASTCommon.h"
 #include "ASTReaderInternals.h"
-#include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/Utils.h"
 #include "clang/Sema/Sema.h"
 #include "clang/Sema/Scope.h"