Fix mapping show images in tmdb_api.

lib/api_tmdb/tmdb_api.py

@@ -634,13 +634,15 @@ class TmdbIndexer(TVInfoBase):
             show_obj.banner_loaded = True
             show_obj.fanart_loaded = True
             for img_type, img_list in iteritems(show_data['images']):
-                img_type = {'backdrops': TVInfoImageType.fanart, 'posters': TVInfoImageType.poster}.get(img_type)
+                map_img_type = {'backdrops': TVInfoImageType.fanart, 'posters': TVInfoImageType.poster}.get(img_type)
+                if None is not map_img_type:
                     for img in img_list:
-                    show_obj.images.setdefault(img_type, []).append(
+                        show_obj.images.setdefault(map_img_type, []).append(
                             TVInfoImage(
-                            image_type=img_type,
+                                image_type=map_img_type,
                                 sizes={
-                                t_s: '%s%s%s' % (self.img_base_url, self.size_map[img_type][t_s], img['file_path'])
+                                    t_s: '%s%s%s' % (self.img_base_url, self.size_map[map_img_type][t_s],
+                                                     img['file_path'])
                                     for t_s in [TVInfoImageSize.original, TVInfoImageSize.medium, TVInfoImageSize.small]
                                 },
                                 rating=img['vote_average'],