Fix bug with GuildChannel.edit and Role.edit with positions.

I did not update the HTTP code for these two methods.

discord/abc.py

@@ -124,8 +124,8 @@ class GuildChannel:
             raise InvalidArgument('Channel position cannot be less than 0.')
 
         http = self._state.http
-        url = '{0}/{1.guild.id}/channels'.format(http.GUILDS, self)
-        channels = [c for c in self.guild.channels if isinstance(c, type(self))]
+        cls = type(self)
+        channels = [c for c in self.guild.channels if isinstance(c, cls)]
 
         if position >= len(channels):
             raise InvalidArgument('Channel position cannot be greater than {}'.format(len(channels) - 1))
@@ -143,7 +143,7 @@ class GuildChannel:
             channels.insert(position, self)
 
         payload = [{'id': c.id, 'position': index } for index, c in enumerate(channels)]
-        yield from http.patch(url, json=payload, bucket='move_channel')
+        yield from http.move_channel_position(self.guild.id, payload)
 
     def _fill_overwrites(self, data):
         self._overwrites = []

discord/http.py

@@ -475,6 +475,10 @@ class HTTPClient:
 
         return self.request(Route('PATCH', '/channels/{channel_id}', channel_id=channel_id), json=payload)
 
+    def move_channel_position(self, guild_id, positions):
+        r = Route('PATCH', '/guilds/{guild_id}/channels', guild_id=guild_id)
+        return self.request(r, json=positions)
+
     def create_channel(self, guild_id, name, channe_type, permission_overwrites=None):
         payload = {
             'name': name,
@@ -598,6 +602,10 @@ class HTTPClient:
         r = Route('POST', '/guilds/{guild_id}/roles', guild_id=guild_id)
         return self.request(r, json=fields)
 
+    def move_role_position(self, guild_id, positions):
+        r = Route('PATCH', '/guilds/{guild_id}/roles', guild_id=guild_id)
+        return self.request(r, json=positions)
+
     def add_role(self, guild_id, user_id, role_id):
         r = Route('PUT', '/guilds/{guild_id}/members/{user_id}/roles/{role_id}',
                   guild_id=guild_id, user_id=user_id, role_id=role_id)

discord/role.py

@@ -175,7 +175,6 @@ class Role(Hashable):
             return  # Save discord the extra request.
 
         http = self._state.http
-        url = '{0}/{1}/roles'.format(http.GUILDS, self.guild.id)
 
         change_range = range(min(self.position, position), max(self.position, position) + 1)
         sorted_roles = sorted((x for x in self.guild.roles if x.position in change_range and x.id != self.id),
@@ -189,7 +188,7 @@ class Role(Hashable):
             roles.append(self.id)
 
         payload = [{"id": z[0], "position": z[1]} for z in zip(roles, change_range)]
-        yield from http.patch(url, json=payload, bucket='move_role')
+        yield from http.move_role_position(role.guild.id, payload)
 
     @asyncio.coroutine
     def edit(self, **fields):