[1.2.X] Fixed #14301 -- Further refine changes made in r14217 to support...

[1.2.X] Fixed #14301 -- Further refine changes made in r14217 to support non-ASCII characters in email addresses. Thanks, Claude Peroz and Andi Albrecht.

Backport from trunk (r15006).

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15007 bcc190cf-cafb-0310-a4f2-bffc1f526a37