Removed unneeded pytz dependency
Removed unneeded pytz dependency

Former-commit-id: 526cf6115d1ed764c953ce67d4fefbbe2a909ad2
kaustubhcs/PyOpenWorm,gsarma/PyOpenWorm,openworm/PyOpenWorm,hnunner/PyOpenWorm,travs/PyOpenWorm,openworm/PyOpenWorm,gsarma/PyOpenWorm