backend: drop 'check_consecutive_build_fails' script
    
    It hasn't been used for quite some time now, and it is broken (we
    changed our Redis database a lot, so fixing the script would be
    painful).
    
    Now we moved the "copr-ping" feature into Fedora Infra Ansible.git
    configuration, and that is hardly an upstreamable script-work:
    https://pagure.io/fedora-infra/ansible/blob/881764b3458dcb17ca9e985fb84c33446f4da153/f/roles/copr/backend/tasks/copr-ping.yml