Use GuildChannel abc for CategoryChannel edit
Use GuildChannel abc for CategoryChannel edit

I noticed nothing happened when I did
`ch.edit(overwrites=oh.overwrites)`

`http.edit_channel` doesn't do anything with the `overwrites` keyword,
it's processed as `permission_overwrites` instead which `self._edit`
takes care of.

I feel this was an oversight at some point.

Harmon758/discord.py,Harmon758/discord.py,khazhyk/discord.py,Rapptz/discord.py,rapptz/discord.py