LU-8929 lfsck: dumper gets current position properly

LU-8929 lfsck: dumper gets current position properly

It is normal that the LFSCK iteration has been done when the
dump hanlder found the status as LS_SCANNING_PHASE1, it may
because of race, or the LFSCK failed to update the status.
Under such cases, the dump handler will use the position in
the last checkpoint as the current position. It may be not
100% accurate, but not serious issue.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: I672258baa9d0b0aa8ec12249c13b2b147a274ab4
Reviewed-on: https://review.whamcloud.com/24869
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>