Remove direct uses of checkIsActive, replace with helper methods This makes _checkIsActive a lot easier to understand, and makes the access checkers involved a lot more explicit. Patch by: Sverre Rabbelier

# Geo-enabled Sitemap classes.
from django.contrib.gis.sitemaps.georss import GeoRSSSitemap
from django.contrib.gis.sitemaps.kml import KMLSitemap, KMZSitemap