Description of problem:
Automatic test with flow: Run once vm with "Start in paused" enabled, and when vm in pause mode, change vm cd, fail for change vm cd.  
http://jenkins-ci.eng.lab.tlv.redhat.com/job/rhevm_3.5_automation_coretools_two_hosts_restapi_vms_nfs_rest_factory/

Version-Release number of selected component (if applicable):
Starting 3.5.0-0.1000.45.3a6d9b8.master.el6ev
and still failing on 3.5.0-0.1000.90.35c6d9e.beta.el6ev (last run)

How reproducible:
100

Additional info:
vdsm.log:
========
Thread-1314::DEBUG::2014-09-22 12:58:40,176::__init__::467::jsonrpc.JsonRpcServer::(_serveRequest) Calling 'VM.changeCD' in bridge with {u'driveSpec': u'/rhev/data-center/mnt/multipass.eng.lab.tlv.redhat.com:_export_images_qa_shared__iso__domain/7233a711-98e8-4c3c-bcfa-44c4bcc4f6c6/images/11111111-1111-1111-1111-111111111111/en_windows_7_enterprise_x64.iso', u'vmID': u'2a12e984-ba1e-47e8-9c2c-bd7910ce8630'}
JsonRpcServer::DEBUG::2014-09-22 12:58:40,176::__init__::504::jsonrpc.JsonRpcServer::(serve_requests) Waiting for request
Thread-1314::INFO::2014-09-22 12:58:40,180::clientIF::331::vds::(prepareVolumePath) prepared volume path: /rhev/data-center/mnt/multipass.eng.lab.tlv.redhat.com:_export_images_qa_shared__iso__domain/7233a711-98e8-4c3c-bcfa-44c4bcc4f6c6/images/11111111-1111-1111-1111-111111111111/en_windows_7_enterprise_x64.iso
Thread-1314::WARNING::2014-09-22 12:58:40,305::clientIF::361::vds::(teardownVolumePath) Drive is not a vdsm image: None
Traceback (most recent call last):
  File "/usr/share/vdsm/clientIF.py", line 354, in teardownVolumePath
    if vm.isVdsmImage(drive):
  File "/usr/share/vdsm/virt/vm.py", line 112, in isVdsmImage
    return all(k in drive for k in required)
  File "/usr/share/vdsm/virt/vm.py", line 112, in <genexpr>
    return all(k in drive for k in required)
TypeError: argument of type 'NoneType' is not iterable
Thread-1314::WARNING::2014-09-22 12:58:40,310::Bridge::210::root::(_typeFixup) Fixing up type VmDevice
Thread-1314::WARNING::2014-09-22 12:58:40,311::Bridge::448::root::(fieldClone) fieldClone: type -> deviceType
. . .

engine.log:
==========
2014-09-22 12:58:40,365 ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.ChangeDiskVDSCommand] (ajp-/127.0.0.1:8702-9) [b12ad9e8-38b0-4280_changeCDWhileRunning_update] Failed in ChangeDiskVDS method, for vds: cinteg09.ci.lab.tlv.redhat.com; host: 10.35.148.56
2014-09-22 12:58:40,365 ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.ChangeDiskVDSCommand] (ajp-/127.0.0.1:8702-9) [b12ad9e8-38b0-4280_changeCDWhileRunning_update] Command ChangeDiskVDSCommand(HostName = cinteg09.ci.lab.tlv.redhat.com, HostId = 3451c38a-e13c-48c1-adeb-42330002f1bb, vmId=2a12e984-ba1e-47e8-9c2c-bd7910ce8630, diskPath=/rhev/data-center/mnt/multipass.eng.lab.tlv.redhat.com:_export_images_qa_shared__iso__domain/7233a711-98e8-4c3c-bcfa-44c4bcc4f6c6/images/11111111-1111-1111-1111-111111111111/en_windows_7_enterprise_x64.iso) execution failed. Exception: NullPointerException: 
2014-09-22 12:58:40,366 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.ChangeDiskVDSCommand] (ajp-/127.0.0.1:8702-9) [b12ad9e8-38b0-4280_changeCDWhileRunning_update] FINISH, ChangeDiskVDSCommand, log id: 6f6cc773
2014-09-22 12:58:40,366 ERROR [org.ovirt.engine.core.bll.ChangeDiskCommand] (ajp-/127.0.0.1:8702-9) [b12ad9e8-38b0-4280_changeCDWhileRunning_update] Command org.ovirt.engine.core.bll.ChangeDiskCommand throw Vdc Bll exception. With error message VdcBLLException: java.lang.NullPointerException (Failed with error ENGINE and code 5001)
2014-09-22 12:58:40,372 ERROR [org.ovirt.engine.core.bll.ChangeDiskCommand] (ajp-/127.0.0.1:8702-9) [b12ad9e8-38b0-4280_changeCDWhileRunning_update] Transaction rolled-back for command: org.ovirt.engine.core.bll.ChangeDiskCommand.
2014-09-22 12:58:40,380 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (ajp-/127.0.0.1:8702-9) [b12ad9e8-38b0-4280_changeCDWhileRunning_update] Correlation ID: b12ad9e8-38b0-4280_changeCDWhileRunning_update, Job ID: 6b0d6ca9-b637-4054-9f33-25e4ef223e58, Call Stack: null, Custom Event ID: -1, Message: Failed to change disk in VM run_once_vm (Host: cinteg09.ci.lab.tlv.redhat.com, User: admin).
2014-09-22 12:58:40,385 ERROR [org.ovirt.engine.api.restapi.resource.AbstractBackendResource] (ajp-/127.0.0.1:8702-9) Operation Failed: [Internal Engine Error]