Affinity group change: "VM stop" message bug

[elenaustyugova]

Steps to reproduce:

1. Go to VM details of a running VM
2. Click "Affinity group change" button
3. Click "Stop" in a system message ("To change VM you need to stop VM. Are you sure you want to stop it?")

VM is stopped, the affinity group is changed, it is ok.

4. Do not close sidebar, click "Affinity group change" button again straight away.

Expected result: Dialogue with existing groups opens directly, no system message.
Actual result: System message about VM stopping appears, though VM is already stopped.