Looking into ci.debian.net, the new failure appears for the first time on 2017-03-14:
https://ci.debian.net/data/packages/unstable/amd64/p/pandas/20170314_082050.autopkgtest.log.gz The debci log also shows an update of tzdata for this time: https://ci.debian.net/data/packages/unstable/amd64/p/pandas/20170314_082050.log so I would suspect this as the cause as well.
