LU-7098 osd-ldiskfs: don't alloc inode directly

LU-7098 osd-ldiskfs: don't alloc inode directly

We should alloc ldiskfs_inode_info instead alloc inode
directly. Else will overflow in follow ldiskfs_add_entry.

Signed-off-by: Yang Sheng <yang.sheng@intel.com>
Change-Id: Ib88f847ea8f160f6f0d0c7e7e680247d7ec96fb6
Reviewed-on: http://review.whamcloud.com/16804
Reviewed-by: Fan Yong <fan.yong@intel.com>
Tested-by: Jenkins
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>