scripts/setup.sh: Fix. Variable virtio_names used as array contains empty first element.

It fixes change 474989.

"for blkname in $blknames; do"
was changed to
"for blkname in "${blknames[@]}"; do"
if blknames=" vda" then first blkname="" and
linux_bind_driver is called for vda although it has active mountpoint

Change-Id: I16d4379db274faa5703230072cfcf8d18a8ef5e6
Signed-off-by: Pawel Kaminski <pawelx.kaminski@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/476061
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

scripts/setup.sh

@@ -159,15 +159,15 @@ function get_nvme_name_from_bdf {
 
 function get_virtio_names_from_bdf {
 	blk_devs=$(lsblk --nodeps --output NAME)
-	virtio_names=''
+	virtio_names=()
 
 	for dev in $blk_devs; do
 		if readlink "/sys/block/$dev" | grep -q "$1"; then
-			virtio_names="$virtio_names $dev"
+			virtio_names+=("$dev")
 		fi
 	done
 
-	eval "$2='$virtio_names'"
+	eval "$2=( " "${virtio_names[@]}" " )"
 }
 
 function configure_linux_pci {