when switching to mpirun, the launcher flags are not set

[seb-wahl]

When I add

computer:
   launcher: mpirun

The final .sad file still contains the launcher_flags from srun and from mpirun. If I use

computer:
   launcher: mpirun
   launcher_flags: ' -example_flag'

the time ... & command in the .sad file contains the correct options.
If I change the slurm.yaml in a way that I add the execution_command to the choose_launcher: block, I always get the correct execution_command for srun or mpirun.
Summary: The launcher_flags in the choose_launcher: block in slurm.yaml are ignored
Independent of that, mpirun does not work yet as mpirun does not use a hostfile. I fixed that in #98 as I need to use mpirun with OpenMPI on nesh @ CAU Kiel

[pgierz]

Does this still happen in the latest version? Could you give a reproducible example? One of the things that came out of the workshop is to create tests (even if just text based), so I would try to add as many "weird behaviors" as I can.