LU-3531 llite: fix "lfs getdirstripe" to show stripe info

LU-3531 llite: fix "lfs getdirstripe" to show stripe info

Fix "lfs getdirstripe", so it can show layout information
of striped directory

[root@testnode tests]# ../utils/lfs getdirstripe /mnt/lustre/test1
/mnt/lustre/test1
lmv_stripe_count: 2
lmv_stripe_offset: 0
mdtidx		 FID[seq:oid:ver]
     0		 [0x280000400:0x1:0x0]
     1		 [0x2c0000400:0x1:0x0]

Signed-off-by: wang di <di.wang@intel.com>
Change-Id: I586f78ee2e0c35d8c3ed10726d5f5e12a4b543e7
Reviewed-on: http://review.whamcloud.com/7228
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>