- Don't return immediately in check_xucred, check_scm_creds_cmsgcred, and

- Don't return immediately in check_xucred, check_scm_creds_cmsgcred, and
  check_scm_creds_sockcred after initial != NULL checks have been done for
  debugging purposes
- Use more terse names for bintime (bt), cmesgcred (cmcred),
  sockcred (sc), and timeval (tv) [*]
- Add some debug messages to better understand some of the flow of the test
  program

MFC after: 1 week
Requested by: bde [*]
Use of the word "terse" (^.^) corrected by: jhb, rpokala [*]
Sponsored by: EMC / Isilon Storage Division