index: use `index.has_node` in `revlog.addrevision`

Differential Revision: https://phab.mercurial-scm.org/D7323

mercurial/revlog.py

@@ -1995,7 +1995,7 b' class revlog(object):'
             )
 
         node = node or self.hash(rawtext, p1, p2)
-        if node in self.nodemap:
+        if self.index.has_node(node):
             return node
 
         if validatehash: