Python3.5 change from m_reload to m_slot in PyModuleDef

[JanKaul]

Since Version 3.5 the member "m_reload" of the PyModuleDef changed to "m_slots". I think this is currently not the case for the Rust bindings.

PyModuleDef_Slot* m_slots¶

An array of slot definitions for multi-phase initialization, terminated by a {0, NULL} entry. When using single-phase initialization, m_slots must be NULL.

Changed in version 3.5: Prior to version 3.5, this member was always set to NULL, and was defined as:

inquiry m_reload¶

https://docs.python.org/3/c-api/module.html?highlight=pymoduledef#c.PyModuleDef.m_slots