revert Pyston's change about PyBoolObject

bool is technically a subclass of int. Revert that Pyston change to support some extensions.

from_cpython/Include/boolobject.h

@@ -9,10 +9,7 @@ extern "C" {
 #endif
 
 
-// Pyston change: Try to avoid having to support mixing ints and bools
-// typedef PyIntObject PyBoolObject;
-struct _PyBoolObject;
-typedef struct _PyBoolObject PyBoolObject;
+typedef PyIntObject PyBoolObject;
 
 // Pyston change: this is no longer a static object
 PyAPI_DATA(PyTypeObject*) bool_cls;