Description of problem:
Alerts in VM overview tab disappeared after a few seconds

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. Create a VM which is not migratable
2. Visit the VM alerts in overview tab
3. There is an alert about VM is not migratable
4. Wait for some seconds, the alerts is gone
5. Visit VM list page
6. Repeas step 2-4

Actual results:
the alerts is gone

Expected results:
the alerts is always there

Additional info: