Automatic merge from submit-queue
Ignore the available volume when calling DetachDisk
Fix#50207
If user detachs the volume by nova in openstack env, volume becomes
available. If nova instance is been deleted, nova will detach it
automatically and become available. So the "available" is fine since that means the
volume is detached from instance already.
**Release note**:
```release-note
NONE
```
702f23e977