Fixed #13779 -- Can now discover GDAL 1.7 from debian-based packages. Thanks...

Fixed #13779 -- Can now discover GDAL 1.7 from debian-based packages.  Thanks to Leo for bug report and patch.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@13396 bcc190cf-cafb-0310-a4f2-bffc1f526a37