pool: Fix regressions in new HSM subsystem

The argument order for remove callouts was wrong.

Logging was a bit too quiet.

Target: trunk
Request: 2.9
Require-notes: yes
Require-book: no
Acked-by: Karsten Schwank <karsten.schwank@desy.de>
Patch: https://rb.dcache.org/r/7072/