blktrace improvements and fixups

blktrace improvements and fixups

Remove iolog version 1 support, it's just too limited. Version 2 and
blktrace manage file events (add,open,close,tc) on their own and we
can cleanup the file creation if we kill it.

Fixup for_each_file() for no allocated files.

Start of handling notify events for blktrace. We don't see program
notifications, need to look into that.

Properly account io bytes when adding blktrace events, so that the ETA
and io count is correct on replay.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>