fix "make check"

Regenerate testsuite reference data which was necessary after these
fixes:

- commit 3b96baef65ea6c315937f5cd2253c6b6c62636d8
  "sane-desc: fix udev hwdb generation"
- commit 758731489d0d58bab6e4b70db9556038c9f4bb67
  "sane-desc: fix faulty udev logic for SCSI devices"
avoid using string formats insecurely with "-f"

In the process, simplify processing the device list format: don't copy
the format string for writing \0 into it, just iterate over chunks in
the original string.