move library-specific diagnostic headers into library private dirs.  Reduce
redundant #includes.  Patch by Anders Johnsen!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63271 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index f14aba6..4a81f71 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -20,7 +20,7 @@
 #include "SemaOverload.h"
 #include "clang/AST/DeclBase.h"
 #include "clang/Parse/Action.h"
-#include "clang/Basic/DiagnosticSema.h"
+#include "clang/Sema/SemaDiagnostic.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/SmallPtrSet.h"