dist/common/scripts/scylla_raid_setup: skip blkdiscard when disk is not supported TRIM
dist/common/scripts/scylla_raid_setup: skip blkdiscard when disk is not supported TRIM

Since we unconditionally running blkdiscard on disks, we may get ioctl error
message on some disks which does not support TRIM.

This can be ignore but it's bad UX, so let's skip running blkdiscard when TRIM
is not supported on the disk.

Fixes #2774

Signed-off-by: Takuya ASADA <4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>
Message-Id: <1517992904-13838-1-git-send-email-4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@scylladb.com>

duarten/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,avikivity/scylla,scylladb/scylla