ports/176699: devel/py-celery: fix build with new dateutil

[edwin at FreeBSD.org]

Synopsis: devel/py-celery: fix build with new dateutil

Responsible-Changed-From-To: freebsd-ports-bugs->freebsd-python
Responsible-Changed-By: edwin
Responsible-Changed-When: Wed Mar 6 20:01:39 UTC 2013
Responsible-Changed-Why: 
freebsd-python@ wants this port PRs (via the GNATS Auto Assign Tool)

http://www.freebsd.org/cgi/query-pr.cgi?pr=176699