Created attachment 1201156 [details]
engine.log

Description of problem:
Remove VM with disk and choose not to remove disk via REST.

REST request:

DELETE /api/vms/<uuid> HTTP/1.1
Accept: application/xml
Content-type: application/xml

<action>
    <vm>
        <disks>
            <detach_only>true</detach_only>
        </disks>
    </vm>
</action>

also try with diskattachments: 
<action>
    <vm>
        <diskattachments>
            <detach_only>true</detach_only>
        </diskattachments>
    </vm>
</action>

Version-Release number of selected component (if applicable):
rhevm-4.0.4.2-0.1.el7ev.noarch

How reproducible:
100 %

Steps to Reproduce:
1. Create Vm with disk
2. Remove VM and de-attach disk with REST 

Actual results:
VM and Disk deleted

Expected results:
VM will be deleted 
Disk will not be deleted