Ensured that `makemessages` doesn't leave any temporary file over if the...

Ensured that `makemessages` doesn't leave any temporary file over if the parsing of a template file fails. Refs #8536.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17240 bcc190cf-cafb-0310-a4f2-bffc1f526a37