qemu: stop qemu process when virtiofsd quits

If virtiofsd fails to initialize and stops unexpected,
qemu might hang forever. We just stop the qemu process.
Resource cleanup will be done by others.

Fixes: #1690
Signed-off-by: Peng Tao <bergwolf@hyper.sh>

virtcontainers/qemu.go

@@ -645,6 +645,7 @@ func (q *qemu) startSandbox(timeout int) error {
 				}
 			}
 			q.Logger().Info("virtiofsd quits")
+			q.stopSandbox()
 		}()
 		timeoutDuration := time.Duration(timeout) * time.Second
 		select {