Enabled the existing admin Selenium tests to be run with Internet Explorer....

Enabled the existing admin Selenium tests to be run with Internet Explorer. Note that some tweaks had to be made, in particular as IE7 has limited capabilities regarding CSS selectors.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17666 bcc190cf-cafb-0310-a4f2-bffc1f526a37