prevent tests from failing between 11pm and 11:59pm

should prevent the common failures of this format:
```
======================================================================
FAIL: test_create (corehq.apps.sofabed.tests.test_casedata.CaseDataTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/czue/src/commcare-hq/corehq/apps/sofabed/tests/test_casedata.py", line 72, in test_create
    self.assertEqual(date.today(), action.date.date())
AssertionError: datetime.date(2014, 12, 3) != datetime.date(2014, 12, 2)
```