[1.2.X] Added imports for some new unittest modules. Thanks to Stephan Jaekel.

Backport of r13892 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@13913 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/utils/tests.py

@@ -12,4 +12,7 @@ from text import *
 from simplelazyobject import *
 from decorators import *
 from functional import *
-
+from timesince import *
+from datastructures import *
+from tzinfo import *
+from datetime_safe import *