Comment 1 for bug 1546778

I think there is no need to delete image from glance, this bug occurs
because migration is triggered during resize. But backing file is not copied in this
code flow, i would like to propose patch that fix this problem.

Steps to reproduce:

1. Deploy openstack with 2 or more computes.
2. Boot one or more instances on the same compute with flavor micro or tiny.
3. Resize one of the instances, that probably will cause migration.

If instance disk has backing file - migration will fail because in current implementation
backing files are not copied from one compute to another.