ci: Make the FDO_UPSTREAM_REPO variable global

ci-fairy doesn't know how to to look at $CI_MERGE_REQUEST_PROJECT_PATH right now, so if we don't manually set $FDO_UPSTREAM_REPO, ci-fairy will (without verbose logging turned on) silently fall back on the source repository project path for finding the branch point. This might fail if the owner of the source repository hasn't updated the master branch of their fork.

Signed-off-by: Jonas Ådahl jadahl@gmail.com