[1.2.X] Fixed regression introduced in r13755 that prevented the running of...

[1.2.X] Fixed regression introduced in r13755 that prevented the running of the GEOS/GDAL test suites without configuring Django settings; moved reference geometry data from Python module to compressed JSON fixture; put in workaround in tests for GDAL bug #3783.

Backport of r14414 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14415 bcc190cf-cafb-0310-a4f2-bffc1f526a37