[E621:pool] fix AttributeError (#7265)

fixes regression introduced in 24bbcbcfa3

gallery_dl/extractor/danbooru.py

@@ -282,10 +282,11 @@ class DanbooruPoolExtractor(DanbooruExtractor):
     example = "https://danbooru.donmai.us/pools/12345"
 
     def metadata(self):
-        return self._collection_metadata(self.groups[-1], "pool")
+        self.pool_id = self.groups[-1]
+        return self._collection_metadata(self.pool_id, "pool")
 
     def posts(self):
-        return self._collection_posts(self.groups[-1], "pool")
+        return self._collection_posts(self.pool_id, "pool")
 
 
 class DanbooruFavgroupExtractor(DanbooruExtractor):

gallery_dl/version.py

@@ -6,5 +6,5 @@
 # it under the terms of the GNU General Public License version 2 as
 # published by the Free Software Foundation.
 
-__version__ = "1.29.3"
+__version__ = "1.29.4-dev"
 __variant__ = None