Fixing pickling of tz classes, as reported by Andreas Köhler <KoehlerAndreas@web.de>.
Fixing pickling of tz classes, as reported by
Andreas Köhler <KoehlerAndreas@web.de>.

Bachmann1234/dateutil,jenshnielsen/dateutil,emsoftware/python-dateutil,sprymix/python-dateutil,mjschultz/dateutil,abalkin/dateutil,pganssle/dateutil-test-codecov,sprymix/dateutil,adamgreig/python-dateutil,pganssle/dateutil-test-codecov,abalkin/dateutil