Workaround HTTP 2 issues on OSTree images

Similar to the approach in 547b7f13 now disable HTTP 2 to allow OSTree images to be able to pass tests. Currently some OSTree tests sporadically fail with logs:

Ostree upgrade failed: While fetching https://images.apertis.org/ostree/repo/objects/17/8775a66b5a81648773fa23599c49b15012af2af125387eb66cec8c4551f685.filez: [55] Failed sending data to the peer

Upstream issue: https://github.com/ostreedev/ostree/issues/2570

apertis-issues#389 (closed)

Signed-off-by: Walter Lozano walter.lozano@collabora.com