A glanceclient patch[1] that causes the CPU to be used more efficiently has
been backported to 17.1[2]. We need to make sure this is also available in
18.1.

This will not required validation: this bug is just about making sure the patch
is included and there is no performance regression.

[1] https://review.opendev.org/q/I8b6e19621fc989526b02319d88fcfde88a17eee0
[2] https://code.engineering.redhat.com/gerrit/c/python-glanceclient/+/452757