Created attachment 1297444 [details]
vdsm, supervdsm and engine logs

Description of problem:
When trying to hot unplug vNIC that use queues the operation fails with error:
jsonrpc.Executor/6::ERROR::2017-07-13 10:14:31,966::vm::2347::virt.vm::(hotunplugNic) vmId=`c4075e4c-581f-44d1-a271-cb078ee1eee3`::Hotunplug failed
Traceback (most recent call last):
  File "/usr/share/vdsm/virt/vm.py", line 2338, in hotunplugNic
    self._dom.detachDevice(nicXml)
  File "/usr/share/vdsm/virt/virdomain.py", line 68, in f
    ret = attr(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/vdsm/libvirtconnection.py", line 124, in wrapper
    ret = f(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/vdsm/utils.py", line 1313, in wrapper
    return func(inst, *args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 1147, in detachDevice
    if ret == -1: raise libvirtError ('virDomainDetachDevice() failed', dom=self)
libvirtError: unsupported configuration: Unknown interface <driver name=''> has been specified


Version-Release number of selected component (if applicable):
vdsm-4.17.42-1.el7ev.noarch

How reproducible:
100%

Steps to Reproduce: 
1. Start VM with vNIC that use queues
2. Try to host unplug the vNIC


Additional info:
jsonrpc.Executor/6::INFO::2017-07-13 10:14:31,943::vm::2316::virt.vm::(hotunplugNic) vmId=`c4075e4c-581f-44d1-a271-cb078ee1eee3`::Hotunplug NIC xml: <interface type="bridge">
        <address bus="0x00" domain="0x0000" function="0x0" slot="0x09" type="pci"/>
        <mac address="00:1a:4a:16:88:90"/>
        <model type="virtio"/>
        <source bridge="ovirtmgmt"/>
        <filterref filter="vdsm-no-mac-spoofing"/>
        <link state="up"/>
        <driver name="" queues="5"/>
        <bandwidth/>
</interface>