LU-5424 mdt: allow open by FID to create striping

In mdt_create_data() remove the check on parent that prevent open by
FID from creating striping. In sanity.sh check that open by FID may
create striping.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I4d948d83dca8a542b15945d8bf3b9feaded0f5ef
Reviewed-on: http://review.whamcloud.com/11248
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: wangdi <di.wang@intel.com>