[CodeGen] Move EHScopeStack into its own header

CGCleanup.h isn't meant to be included by all of CodeGen according to
John.

llvm-svn: 184321
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 9071e07..b7e2086 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -15,9 +15,9 @@
 #define CLANG_CODEGEN_CODEGENFUNCTION_H
 
 #include "CGBuilder.h"
-#include "CGCleanup.h"
 #include "CGDebugInfo.h"
 #include "CGValue.h"
+#include "EHScopeStack.h"
 #include "CodeGenModule.h"
 #include "clang/AST/CharUnits.h"
 #include "clang/AST/ExprCXX.h"