admin-verify: expect a number of errors to be returned It's the responsibility of the check to handle errors, we only care about the total count to sum up the check's work. We use `admin::verify -c dirstate` to test this path at least somewhat.

admin-verify: fix error message handling `dirstate.verify` used to return tuples but does not anymore, it returns the pre-formatted error message, which is a nicer interface anyway.

admin-verify: pass p1 down to the dirstate function This was forgotten and can break with certain kinds of corruption.