LU-7354 osd: avoid NULL pointer in osd_obj_update_entry

LU-7354 osd: avoid NULL pointer in osd_obj_update_entry

In osd_obj_update_entry(), the variable @oi_fid may be NULL.
We need to check such case before further using it to avoid
accessing invalid RAM.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Ibf47e949d69f0b9e5657a6dce2007fe4f6f1a9f6
Reviewed-on: http://review.whamcloud.com/17010
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>