Updated openstack/openstack
Project: openstack/nova  87e1603f6ce0925f5ce39f5e671ed3c99fe2de8b

Allow to unshelve instance booted from volume

When we shelve an instance, volumes are not detached from cinder to kept
them 'In-Use' in cinder
But when you unshelve this instance, nova ask cinder the reattach theses
volumes. This fails, because volume cannot be attached twice.

This patch permits when we ask the libvirt DriverBlockDevice to attach a
device to the instance to bypass the cinder attachement code that is not needed
when we unshelve an instance, because the cinder volume is kept 'In-use'
during the 'shelved' state.

Co-Authored-By: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@cloudwatt.com>
Closes-bug: #1305399
Change-Id: I780a9407feeb48ecd3e295508ce3e6bc3b09d3e6