LU-4557 ext4: recalc percpu counters after journal

LU-4557 ext4: recalc percpu counters after journal

the percpu counters is initialized before replaying the journal,
but after the journal it should be recalculate to deal with the
possibility of the percpu counters getting updated by the journal
replay.

the issue has been fixed in the new kernels (RHEL6 2.6.32-431.5.1,
SLES11SP3 3.0.101-0.15), then it is not needed for these kernels.

Change-Id: I5dfa0696b5ccd404b1add9ad6e2b0877d86a35b2
Signed-off-by: Hongchao Zhang <hongchao.zhang@intel.com>
Reviewed-on: http://review.whamcloud.com/9908
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>