kernel - Work through some memory leaks in dsched

kernel - Work through some memory leaks in dsched

* Add a uninitbufbio() function to complement initbufbio().  Also move
  BUF_LOCKINIT() into initbufbio() and BUF_LOCKFREE() into uninitbufbio().

* There are several device drivers and other places where the struct buf
  is still being allocated manually (verses using getpbuf()).  These were
  kfree()ing the buffer without dealing with e.g. dsched_exit_buf().

  Have uninitbufbio() call dsched_exit_buf() and adjust the various manual
  allocations/frees of struct buf to call uninitbufbio() before kfree()ing.
  Also remove various manual calls to BUF_LOCKFREE() (which is now done
  inside uninitbufbio()).

* This should hopefully deal with the memory leaks but there could be a
  few left.

Reported-by: "Steve O'Hara-Smith" <steve@sohara.org>