[1.2.X] Fixed #13934 -- `GeoSQLCompiler.get_default_columns` was missing...

[1.2.X] Fixed #13934 -- `GeoSQLCompiler.get_default_columns` was missing `local_only` keyword argument.  Thanks, Simon Law, for bug report and initial patch.

Backport of r13439 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@13440 bcc190cf-cafb-0310-a4f2-bffc1f526a37