jjb: switch crowbar testbuild to github_pr
jjb: switch crowbar testbuild to github_pr

The tool github-status is obsolete and
github_pr will replace it. After switching
the trigger jobs now the worker jobs also
do the switch.

SUSE-Cloud/automation,SUSE-Cloud/automation,SUSE-Cloud/automation,SUSE-Cloud/automation,aspiers/automation,gosipyan/automation,aspiers/automation,gosipyan/automation,gosipyan/automation,aspiers/automation,gosipyan/automation,aspiers/automation