Description of problem:

Try to cold migrate VM with shared disk, when the other VMs (which are using current VM's shared disks) are running, the message(to suggest user poweroff these VMs) only list one VM but not all the VMs' name, need to update the message to include all related VM names

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

2.7.11

How reproducible:

Always

Steps to Reproduce:

1) Prepare VM1: st1 and VM2: st2, each VM with 3 disks (2 shared disks),

    VM3: st3 with 2 disks (use shared disk: d2 of VM1),

    VM4: st4 with 3 disks ( use shared disk d2 of VM2, use shared disk d3 of VM1 )

2) Create a cold migration plan, get the error message:

"Virtual Machins"[mtv-func-win2022-st4]" are running with attached shared disk, please power them off..."

3) Shutoff the VM: mtv-func-win2022-st4 on source, get error message:

   "Virtual Machins"[mtv-func-win2022-st3]" are running with attached shared disk, please power them off..."

Actual results:

In step 2: The error message only suggest to poweroff VM st4, then in step 3 suggest to poweroff VM st3 

Expected results:

In step2: Update the message to include all the VM names which is using the shared disks in current VM, suggest to poweroff them

Additional info: