context: fix filectx.parents() bug introduced when editing 180a3eee4b75

mercurial/context.py

@@ -281,7 +281,7 b' class filectx(object):'
         fl = self._filelog
         pl = [(p, n, fl) for n in self._filelog.parents(self._filenode)]
 
-        r = self.renamed()
+        r = self._filelog.renamed(self._filenode)
         if r:
             pl[0] = (r[0], r[1], None)