Tweaked the admin validation code to make things a bit easier to read. Tracing

through all the underscore-prefixed and wrapped functions was a bit trying and
some of the names were misleading. No functional changes. Primarily, this is
just bringing the style into line with the rest of the codebase.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8604 bcc190cf-cafb-0310-a4f2-bffc1f526a37