LU-4557 ldiskfs: init statfs variables after journal

LU-4557 ldiskfs: init statfs variables after journal

in ext4_fill_super, the variables related to statfs
should be initialized after journal recovery is completed.
otherwise, if a large number of blocks were being allocated
before the filesystem crashed, then the blocks and inode
counters may become negative during use and report incorrect
values to statfs call.

Change-Id: Id7e3f61ce73f5499a6176c336c7931a47f6f76de
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: http://review.whamcloud.com/9277
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Emoly Liu <emoly.liu@intel.com>