hidden: drop cache on hiddenrevs property

The `filteredrevs` function already have a cache mechanism. And this cache in
invalidated at the same time than the current property cache. So we drop the
cache on the property.

The property itself is going to be dropped soon.

mercurial/localrepo.py

@@ -350,7 +350,8 @@ class localrepository(object):
             self.ui.warn(msg % len(list(store)))
         return store
 
-    @unfilteredpropertycache
+    @property
+    @unfiltered
     def hiddenrevs(self):
         """hiddenrevs: revs that should be hidden by command and tools
 
@@ -961,8 +962,6 @@ class localrepository(object):
     def invalidatevolatilesets(self):
         self.filteredrevcache.clear()
         obsolete.clearobscaches(self)
-        if 'hiddenrevs' in vars(self):
-            del self.hiddenrevs
 
     def invalidatedirstate(self):
         '''Invalidates the dirstate, causing the next call to dirstate