Updated openstack/openstack
Project: openstack/nova  cb380e817228c8bf06cd0029a4adf2938cdfd769
null
Move vbd plug/unplug into session object

To make it easier not to miss the VBD plug/unplug workaround I have
moved this into the xenapi object, overriding the regular method.

Change-Id: Ia0e677824b2bf700c5fb73a75c335f74a6ebb6a2