Add a trace for jobsub_cmd commands

When a user runs "jobsub_q", we get a great trace, all the way until the actual `condor_q` is run. This happens here:

https://github.com/fermitools/jobsub_lite/blob/e8a0245f620b84781a86cc775fab1fdbfb4c3ddc/bin/jobsub_cmd#L267

It would be nice to get a trace there too so we can determine if there's an issue with condor_* commands.