MAINT: Remove temporary nullctx alias.

zipline/utils/test_utils.py

@@ -8,10 +8,6 @@ from numpy.testing import assert_array_equal
 import operator
 from zipline.finance.blotter import ORDER_STATUS
 from zipline.utils import security_list
-# FIXME: This is downstream compat.  If it's still here by August 5, 2015,
-# please yell at Scott Sanderson.
-from zipline.utils.control_flow import nullctx  # noqa
-
 from six import (
     itervalues,
 )