clan_lib flake: check the whole tree even if we fetched all keys before

This is needed because nix garbage collection can remove store paths. So
the cache can become invalid because a path needs to be rebuild.

pkgs/clan-cli/clan_lib/flake/flake.py

@@ -345,7 +345,8 @@ class FlakeCacheEntry:
             return True
 
         if selectors == []:
-            return self.fetched_all
+            selector = Selector(type=SelectorType.ALL)
+        else:
             selector = selectors[0]
 
         # we just fetch all subkeys, so we need to check of we inserted all keys at this level before