R1:0ed767b967b3

Fix a couple of partition migration bugs

Summary:
Ref T11044. Few issues here:

- The `PhutilProxyException` is missing an argument (hit this while in read-only mode).
- The `$ref_key` is unused.
- When you add a new master to an existing cluster, we can incorrectly apply `.php` patches which we should not reapply. Instead, mark them as already-applied.

Test Plan:
- Poked this locally, but will initialize `secure004` as an empty master to be sure.

Reviewers: chad, avivey

Reviewed By: avivey…