make live test config loading more flexible
make live test config loading more flexible

with this change we support loading from a job config yaml that has the format:

    ---
    adapter: "torque"
    host: "owens-batch.ten.osc.edu"
    lib: "/opt/torque/lib64"
    bin: "/opt/torque/bin"
    version: "6.0.1"

or the format of a cluster config file such as:

    ---
    v2:
      job:
        adapter: "torque"
        host: "owens-batch.ten.osc.edu"
        lib: "/opt/torque/lib64"
        bin: "/opt/torque/bin"
        version: "6.0.1"

This way we can execute the tests like so:

    OSC_DEFAULT_ACCOUNT=PZS0714 LIVE_CLUSTER_CONFIG=/etc/ood/config/clusters.d/owens.yml bundle exec rspec

or with a locally defined simple job config:

    OSC_DEFAULT_ACCOUNT=PZS0714 LIVE_CLUSTER_CONFIG=owens_job.yml bundle exec rspec

OSC/ood_core,OSC/ood_core,OSC/ood_core