Description of problem:
Create a running VM, then add a watchdog device, then change the device. After that, wait until the VM boot completely, then try to remove the device, the device could not be removed immediately

Version-Release number of selected components (if applicable):
cockpit-297-1.el8.ppc64le
cockpit-machines-297-1.el8.noarch
libvirt-dbus-1.3.0-2.module+el8.9.0+18724+20190c23.ppc64le

How reproducible:
100%

Steps to Reproduce:
1 Create a running VM, then enter the VM detail page
2 Add a watchdog device which is "Reset"
3 Change the watchdog device to "Pause"
4 Wait until the VM boot completely
5 Try to remove the watchdog device
6 Shut off the VM

Actual results:
1 After step 5, the watchdog device will not be detached immediately
2 After step 6, the watchdog device is detached

Expected results:
1 After step 5, the watchdog device should be detached immediately
2 After step 6, the watchdog device should be still detached

Additional info: