compat: fix instabilities compat We added an instabilities method for old version of Mercurial. But we returned an old value for orphan changesets, the one before the big evolve renaming. Fix the return value to match the new return values.

syntax: re
/figures/[^/]+\.png$
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
\.err$
^tests/easy_run.sh$
^build/
^dist/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$
tests/\.testtimes