Remove builtins imports

This module is not intended to be used directly in most cases, per:
https://docs.python.org/3/library/builtins.html

None of our usages warrant the explicit import. We also avoid some
confusion as folks dig to see what we are doing to require
importing builtins directly.

evennia/comms/channelhandler.py

@@ -23,8 +23,6 @@ update() on the channelhandler. Or use Channel.objects.delete() which
 does this for you.
 
 """
-from builtins import object
-
 from django.conf import settings
 from evennia.commands import cmdset, command
 from evennia.utils.logger import tail_log_file

evennia/comms/models.py

@@ -17,8 +17,6 @@ Channels are central objects that act as targets for Msgs. Accounts can
 connect to channels by use of a ChannelConnect object (this object is
 necessary to easily be able to delete connections on the fly).
 """
-from builtins import object
-
 from django.conf import settings
 from django.utils import timezone
 from django.db import models