override context manager does not return to deactivated state

[David Nelson Adamec]

From a shell, I'm able to do the following:

In [1]: from django.utils import translation

In [2]: translation.get_language()

In [3]: with translation.override('fr'):
   ...:     pass
   ...:

In [4]: translation.get_language()
Out[4]: 'fr'

override usually reverts to the previous language upon leaving the context manager, so this behavior seems unexpected.

This is new in Django 1.8: before, get_language() returned the default language, so the default language would be activated after override finished. Now get_language() returns None when there is no active catalog, so override attempts to activate None, which has no effect.