Run dask+SGE backend without SETSHELL = starvation
It's being a while we have this issue, but I've never materialized it here.
When a script that uses dask+SGE backend is executed at Idiap without a
SETSHELL grid, the script hangs forever waiting for a worker.
We need to, i-) either throw an exception once
qsub fails to be executed or ii-) do like it's done in gridtk (triggers this automatically).