R1:38636a39cf2d

Allow modern `phd stop` to stop old daemons cleanly

Summary:
Ref T7352. Make sure modern `phd stop` can still read the old PID file format and stop the daemons, at least for now.

Without this, `stop` still detects them and tells you to `stop --force`, which works, but this makes things a good deal cleaner.

Test Plan: Ran `phd stop` from master, then `phd stop` from this revision. Saw old daemons stop cleanly.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7352…