vfs: Fix deprecation warning in Python 3.10 (
issue6520)
Differential Revision: https://phab.mercurial-scm.org/D10710
revlog: rename `indexdata` to entry_data
Same reasoning as the previous changeset, we might not be looking at index data
here.
Differential Revision: https://phab.mercurial-scm.org/D10602