s3: Improve error message in debug log
s3: Improve error message in debug log

middelink/restic,kurin/restic,jayme-github/restic,ar-jan/restic,jayme-github/restic,restic/restic,fawick/restic,ar-jan/restic,restic/restic,kurin/restic,fawick/restic,middelink/restic