Unnecessary 'module unload' commands in the generated job script

[vkarak]

Here is an example output for the PrgEnv-pgi environment:

#!/bin/bash -l
#SBATCH --job-name="rrtmgp_check_daint_gpu_PrgEnv-pgi"
#SBATCH --time=0:10:0
#SBATCH --ntasks=1
#SBATCH --partition=debug
#SBATCH --exclusive
#SBATCH --output=/scratch/snx3000/karakasv/reframe-tests/stage/gpu/rrtmgp_check/PrgEnv-pgi/rrtmgp_check.out
#SBATCH --error=/scratch/snx3000/karakasv/reframe-tests/stage/gpu/rrtmgp_check/PrgEnv-pgi/rrtmgp_check.err
#SBATCH --constraint=gpu
module load daint-gpu
module unload PrgEnv-cray
module load PrgEnv-pgi
module unload PrgEnv-cray
module load craype-accel-nvidia60
module unload PrgEnv-cray
module load cray-netcdf
module unload PrgEnv-cray
module unload pgi
module load pgi/17.7.0

I think the problem comes from the way we record the conflicts.

Internal issue: https://madra.cscs.ch/scs/reframe/issues/565

[vkarak]

I raised this bug's priority, since it seems to affect the setting the modules attribute and how the module commands are generated.