VM failed to power off via the RHEV Admin Portal

Issue

• A VM was hung and needed to be powered off, but when this was attempted via the RHEV Admin Portal it failed, as seen in the Event Log;

Failed to power off VM vm-a (Host: x.x.x.com User: admin@internal).  

• The engine log showed;

ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.DestroyVDSCommand] (org.ovirt.thread.pool-7-thread-29) [6cf82d75] Command DestroyVDSCommand(HostName = <hostname>, HostId = db8f6903-568a-4663-9a73-5ec3d444aa85, vmId=7122b962-1c19-429e-a55a-b7d8e618015a, force=false, secondsToWait=0, gracefully=false, reason=) execution failed. Exception: VDSErrorException: VDSGenericException: VDSErrorException: Failed to DestroyVDS, error = Virtual machine destroy error, code = 42
...
ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (org.ovirt.thread.pool-7-thread-29) [6cf82d75] Correlation ID: 6cf82d75, Job ID: 37dc3210-c7fe-4834-b34d-53c5bbccde2e, Call Stack: null, Custom Event ID: -1, Message: Failed to power off VM <vm-name> (Host: <hostname>, User: admin@internal).

• The vdsm logs on the host on which the VM was running showed;

Thread-2633538::DEBUG::2016-02-11 03:09:33,211::libvirtconnection::143::root::(wrapper) Unknown libvirterror: ecode: 38 edom: 0 level: 2 message: Failed to terminate process 23608 with SIGTERM: Device or resource busy
Thread-2633538::WARNING::2016-02-11 03:09:33,211::vm::5016::vm.Vm::(_destroyVmGraceful) vmId=`7122b962-1c19-429e-a55a-b7d8e618015a`::Failed to destroy VM '7122b962-1c19-429e-a55a-b7d8e618015a' gracefully
Traceback (most recent call last):
  File "/usr/share/vdsm/virt/vm.py", line 5007, in _destroyVmGraceful
  File "/usr/share/vdsm/virt/vm.py", line 702, in f
  File "/usr/lib/python2.7/site-packages/vdsm/libvirtconnection.py", line 111, in wrapper
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 1043, in destroyFlags
libvirtError: Failed to terminate process 23608 with SIGTERM: Device or resource busy