#2234: trouble in the tutorial server

Changes (by Roland Haas):

I had several issues with the tutorial server at https://etkhub.ndslabs.org/hub/login .

I had frequent disconnects and reconnects. I actually do not think this interrupted my clicking through the Jupyter notebook much,
In the notebook I would see the (*) indicator on simple cells for a long time, likely this when I lost connection.
Finally finished the build, lots of warnings but I think that is usual. When I run the command/cell with create/submit helloworld, there is a Warning about "Warning: Total number of threads and number of cores per node are inconsistent: procs=1, ppn-used=4 (procs must be an integer multiple of ppn-used)." However running the next cell I do finally see the Active (Finished).
Running the next cell show-output, I do not see INFO (helloworld): Hello World! I see messages about no Formaline output.
Running the smaller static_tov gives a more serious error: "The value of the MCA parameter "plm_rsh_agent" was set to a path that could not be found: plm_rsh_agent: ssh : rsh Please either unset the parameter, or check that the path is correct"
And it did not run. And indeed in the plotting cell the data file was not found.