Python 3 tweaks.

src/allmydata/test/test_grid_manager.py

@@ -1,14 +1,6 @@
 """
-Ported to Python 3.
+Tests for the grid manager.
 """
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
-from future.utils import PY2
-if PY2:
-    from future.builtins import filter, map, zip, ascii, chr, hex, input, next, oct, open, pow, round, super, bytes, dict, list, object, range, str, max, min  # noqa: F401
 
 from datetime import (
     timedelta,