availability_zone in request_specs not updated when live migrate vm from one availability zone to another, and if the old aggregate's host demount, vm migration will be failed.
Steps to reproduce
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1) create aggregation: aggregate01 using AZ: zone01, and bonding cmp001;
2) create aggregation: aggregate02 using AZ: zone02, and bonding cmp002;
3) create flavor: test_flavor01, and set properties fit to aggregate01/aggregate02;
4) create instance: test_vm01 using test_flavor01 and --availability-zone set to zome01;
5) check OS-EXT-AZ:availability_zone using 'openstack server show test_vm01' is set to zone01, and the vm's availability_zone in request_specs is set to zone01 too.
6) live migrate test_vm01 to cmp002;
7) check OS-EXT-AZ:availability_zone using 'openstack server show test_vm01' is set to zone02, but the vm's availability_zone in request_specs is still zone01.
8) demount cmp001 on aggregate01, then bonding cmp001 to aggregate02;
9) live migrate test_vm01 without given target node will be failed. because availability_zone in request_specs is still zone01.
I think the value of availability_zone in request_specs should be updated, and the vms should use new availability_zone in request_specs when scheduling.
Fix proposed to branch: master
Review: https:/