Removed unused methods in GIS adapter.

django/contrib/gis/db/backends/base/adapter.py

@@ -14,6 +14,3 @@ class WKTAdapter(object):
 
     def __str__(self):
         return self.wkt
-
-    def prepare_database_save(self, unused):
-        return self

django/contrib/gis/db/backends/postgis/adapter.py

@@ -42,6 +42,3 @@ class PostGISAdapter(object):
         "Returns a properly quoted string for use in PostgreSQL/PostGIS."
         # psycopg will figure out whether to use E'\\000' or '\000'
         return str('ST_GeomFromEWKB(%s)' % self._adapter.getquoted().decode())
-
-    def prepare_database_save(self, unused):
-        return self