Fixed #12445 -- Added ' (single quote), @ (at sign), and ~ (tilde) to safe...

Fixed #12445 -- Added ' (single quote), @ (at sign), and ~ (tilde) to safe characters in `iri_to_uri` function.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@12066 bcc190cf-cafb-0310-a4f2-bffc1f526a37