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

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

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)