iotests: fix the redirection order in 083

It should redirect stdout to /dev/null first,
then redirect stderr to whatever stdout currently points at.
Signed-off-by: NWei Jiangang <weijg.fnst@cn.fujitsu.com>
Message-id: 1461665601-14908-1-git-send-email-weijg.fnst@cn.fujitsu.com
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMax Reitz <mreitz@redhat.com>

tests/qemu-iotests/083

@@ -43,7 +43,7 @@ choose_tcp_port() {
 
 wait_for_tcp_port() {
 	while ! (netstat --tcp --listening --numeric | \
-		 grep "$1.*0\\.0\\.0\\.0:\\*.*LISTEN") 2>&1 >/dev/null; do
+		 grep "$1.*0\\.0\\.0\\.0:\\*.*LISTEN") >/dev/null 2>&1; do
 		sleep 0.1
 	done
 }
@@ -70,7 +70,7 @@ EOF
 		nbd_url="nbd:127.0.0.1:$port:exportname=foo"
 	fi
 
-	$PYTHON nbd-fault-injector.py $extra_args "127.0.0.1:$port" "$TEST_DIR/nbd-fault-injector.conf" 2>&1 >/dev/null &
+	$PYTHON nbd-fault-injector.py $extra_args "127.0.0.1:$port" "$TEST_DIR/nbd-fault-injector.conf" >/dev/null 2>&1 &
 	wait_for_tcp_port "127\\.0\\.0\\.1:$port"
 	$QEMU_IO -c "read 0 512" "$nbd_url" 2>&1 | _filter_qemu_io | _filter_nbd