Fixed #24416 -- uggettext_lazy in email addresses.

[medmunds]

(An alternative fix in sanitize_address would be something like:

if isinstance(addr, six.string_types) or isinstance(addr, Promise):

but I don't see any other Django code that tests for lazy strings in that way.)

[MarkusH]

buildbot, test this please.

[timgraham]

merged in 5993b52, thanks.