LU-6661 dne: setdirstripe should fail if not supported

LU-6661 dne: setdirstripe should fail if not supported

If MDS doesn't support striped directory, creating striped directory
with 'lfs setdirstripe' should fail.

Signed-off-by: Lai Siyao <lai.siyao@intel.com>
Change-Id: I3e1ea394d3d1055230859ff46277179f518692b3
Reviewed-on: http://review.whamcloud.com/15123
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>