Mount a volume on second instances, and the information in cinder is not updated

[wanghongxu]

Description
===========
If you attach a volume to two instances, you will
see that the state of the volume is always attaching.
The state of the volume should not be used to determine
whether or not the cinder is called.

Steps to reproduce
==================
cinder type-create multiattach-type
cinder type-key multiattach-type set "multiattach=<is> True"

cinder create --name multiattach-disk --volume-type multiattach-type --allow-multiattach 1

nova volume-attach instance-id-1 volume-id
nova volume-attach instance-id-2 volume-id

Expected result
===============
volume status is in-use

Actual result
=============
volume status is attaching

code
====
https://github.com/openstack/nova/blob/9aab64558d68ccbd4237cdd3623f1a0f01df3aa6/nova/virt/block_device.py#L406
        if volume['attach_status'] == "detached":
                volume_api.attach(context, volume_id, instance.uuid,
                                  self['mount_device'], mode=mode)

[wanghongxu (wang19930902)]

https://review.openstack.org/#/c/525540/

[OpenStack Infra (hudson-openstack)]

Change abandoned by wanghongxu (<email address hidden>) on branch: master
Review: https://review.openstack.org/525540