- truncate() was always getting a PW[0,EOF] lock for its operation and was

- truncate() was always getting a PW[0,EOF] lock for its operation and was
  checking the start of the lock extent when deciding whether to send a
  discarding intent or not -- we were always throwing away data covered by
  locks that were canceled by truncate().  With it fixed to start its PW lock
  with the truncated size write_append_truncate() passes again.  while I was
  in there I cleaned up some of my more illiterate comment work.