Comment 10 for bug 1837241

In 20190719T013000Z/outputs/CHANGELOG.txt
I saw we merged
https://review.opendev.org/#/c/661512/
Use true for force_raw_images when using ceph image backend

We need this patch for two reasons:

Nova of starlingx has not this patch[0]. We use remote storage(ceph)
as nova backend. If we set force_raw_image to False and use qcow2
format image to boot vms, the vms will fail to boot.

Nova of starlingx will have this patch[0]. If we still use False for
force_raw_images, the nova-compute service will refuse to start.

So that, we must set this force_raw_images to True at all.

[0] https://review.opendev.org/#/c/640271/

However, I double checked our current stein.2 nova, [0] is not included, this is the problem!
We have two options:
1) revert 640271, unblock sanity test first
2) cherry pick [0] to nova stein.2

Zhipeng