iconsub segfaults with `~mpi` if not run with `srun -n 1`

[jonasjucker]

The recipe from Sergey seems to compile the code a bit different then the previous recipe.

It crashes for iconsub in https://github.com/C2SM/icontools/blob/b3bff9b6f726bb645c41f35dadbd4211deedd617/libicontools/src/libicontools/mo_iconsub.f90#L352
if compile with ~mpi.

Running it prefixed with srun -n 1 it runs through.

nml:

&iconsub_nml
    grid_filename = '/capstor/scratch/cscs/ekoene/processing-chain/work/icon-art-CTDAS/2018010100_2018011100/icon/input/icon_europe_DOM01.nc',
    output_type = 4,
    lwrite_grid = .TRUE.,
/
&subarea_nml
    ORDER = "outgrid",
    grf_info_file = '/capstor/scratch/cscs/ekoene/processing-chain/work/icon-art-CTDAS/2018010100_2018011100/icon/input/icon_europe_DOM01.nc',
    min_refin_c_ctrl = 1,
    max_refin_c_ctrl = 120
/

srun -n 1 iconsub --nml=nml works, but `iconsub --nml=nml does not.