- Fix update-alternatives

- Update to version 1.6.2:
+ Prevented the base geometry object of a prepared geometry to be garbage
collected, which could lead to crash Django (#21662).
+ Fixed a crash when executing the changepassword command when the user
object representation contained non-ASCII characters (#21627).
+ The collectstatic command will raise an error rather than default to
using the current working directory if STATIC_ROOT is not set. Combined
with the --clear option, the previous behavior could wipe anything
below the current working directory (#21581).
+ Fixed mail encoding on Python 3.3.3+ (#21093).
+ Fixed an issue where when settings.DATABASES['default']['AUTOCOMMIT'] = False,
the connection wasn’t in autocommit mode but Django pretended it was.
+ Fixed a regression in multiple-table inheritance exclude() queries (#21787).
+ Added missing items to django.utils.timezone.__all__ (#21880).
+ Fixed a field misalignment issue with select_related() and model inheritance (#21413).
+ Fixed join promotion for negated AND conditions (#21748).
+ Oracle database introspection now works with boolean and float fields (#19884).
+ Fixed an issue where lazy objects weren’t actually marked as safe when
passed through mark_safe() and could end up being double-escaped (#21882).