LU-3373 osd-ldiskfs: struct file add f_inode member

LU-3373 osd-ldiskfs: struct file add f_inode member

struct file has a f_inode member. Need initalize
before use it.

Signed-off-by: yang sheng <yang.sheng@intel.com>
Change-Id: I290aaea09c4ff9be7f9d044bf972eb43510933d2
Reviewed-on: http://review.whamcloud.com/7727
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>