LU-4629 osd-ldiskfs: Fix use after free

LU-4629 osd-ldiskfs: Fix use after free

Object 'dir' was dereferenced at line 3343 after being freed
by calling 'kfree' at line 3332.

Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Change-Id: Id8d216868798622f12773b621acf46e81988b954
Reviewed-on: http://review.whamcloud.com/10609
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>