switch from spaces to tabs to match style and awk...

Pointed out by:	brooks
Port t_db.sh to FreeBSD

- The blocksize on FreeBSD is 32kB, not 64kB
- Add some detection for MK_DICT == no; /nonexistent is echoed along with
  atf_skip to ensure that the test will fail if dict(..) is called in the
  non-final stage of the pipeline

Submitted by: pho