vdsm: fix tunneled migration regression

Change-Id: I8958d7a6ba7b48f2390acab7b300cf4e539a550c
Signed-off-by: Peter V. Saveliev <peet@redhat.com>
Signed-off-by: Vinzenz Feenstra <vfeenstr@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/11853
Reviewed-by: Saggi Mizrahi <smizrahi@redhat.com>