Comment 5 for bug 1633219

Was it system-wide change (and reboot is done)? It may be needed if python-apt gets something from outside (e.g. by dbus).
I have no idea, I used update-manager to start the upgrade process and my env:
torkve@yaroot-46:/tmp [2016-10-14 02:01:18]
0 ➜ locale
LANG=ru_RU.UTF-8
LANGUAGE=ru:en
LC_CTYPE="ru_RU.UTF-8"
LC_NUMERIC=ru_RU.UTF-8
LC_TIME=ru_RU.UTF-8
LC_COLLATE="ru_RU.UTF-8"
LC_MONETARY=ru_RU.UTF-8
LC_MESSAGES="ru_RU.UTF-8"
LC_PAPER=ru_RU.UTF-8
LC_NAME=ru_RU.UTF-8
LC_ADDRESS=ru_RU.UTF-8
LC_TELEPHONE=ru_RU.UTF-8
LC_MEASUREMENT=ru_RU.UTF-8
LC_IDENTIFICATION=ru_RU.UTF-8
LC_ALL=