Add test for cvmfs_server check failures

[edytuk]

Fixes #26

[edytuk]

I was not able to find check_status in order to test this

[DrDaveD]

Test it against https://oasis-replica-itb.opensciencegrid.org. You can define a remote server in /etc/cvmfsmon/api.conf (although it will be very slow if run from a machine at CERN). I see it has one repo with a failure, so you can test that aspect as well.

[edytuk]

I tested it against your provided server.

{
"CRITICAL":
    {
        "gc": [{"msg": "error: cvmfs_server failure", "repo": "oasis.opensciencegrid.org"}],
        "updated": [{"msg": "error: cvmfs_server failure", "repo": "oasis.opensciencegrid.org"}]
    }
}

[DrDaveD]

That's the right repo for the check_status failure, but the wrong results. We don't want to flag errors with updated and gc. Please instead add another "check" test. Make it be WARNING if any repository has a failed message.

[edytuk]

I created a new test