LU-9334 lfsck: reset trace file for upgrade case

LU-9334 lfsck: reset trace file for upgrade case

With PFL introduced, the layout LFSCK on-disk trace file
will be changed, that is incompatibile with non-PFL case.
Use new layout LFSCK trace file magic for FPL case, that
will reset the layout LFSCK on-disk trace files for when
upgrade from non-PFL case.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Id3b3fa4a89e5a408700653d8b759b76626c78912
Reviewed-on: https://review.whamcloud.com/26718
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jinshan Xiong <jinshan.xiong@intel.com>