Fixed `MySQLGeoField` to create spatial indexes again.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@9286 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/gis/db/backend/mysql/field.py

@@ -29,7 +29,7 @@ class MySQLGeoField(Field):
               style.SQL_FIELD(qn(self.column)) + ');'
         return sql
 
-    def _post_create_sql(self, style, db_table):
+    def post_create_sql(self, style, db_table):
         """
         Returns SQL that will be executed after the model has been
         created.