Description of problem:

The example stated in the doc (https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.6/html/REST_API_Guide/sect-Methods7.html#Updating_a_Virtual_Machine section 15.7) is in a wrong format and if someone will use it he will not get the expected results. 

The wrong example: 
<vm>
    <cpu>
        <topology sockets="2" cores="1"/>
    </cpu>
</vm>

The correct example:
    <vm>
        <cpu>
          <topology>
            <sockets>4</sockets>
            <cores>2</cores>
            <threads>2</threads>
          </topology>
        </cpu>
     </vm>

If a user will try and run the api with the example from the docs the vm topology will not change.