add-slurm-setting does not overwrite previous setting

[dizak]

The add-slurm-setting option should overwrite the previously saved setting. Instead, typing

mothulity --add-slurm-setting "name=phi exclusive partition=accel exclude=gpu[1-8] processors=32"

gives:

Traceback (most recent call last):
  File "/home/mothulity/miniconda3/bin/mothulity", line 835, in <module>
    main()
  File "/home/mothulity/miniconda3/bin/mothulity", line 530, in main
    slurm_config.add_section(section)
  File "/home/mothulity/miniconda3/lib/python3.6/configparser.py", line 1200, in add_section
    super().add_section(section)
  File "/home/mothulity/miniconda3/lib/python3.6/configparser.py", line 659, in add_section
    raise DuplicateSectionError(section)
configparser.DuplicateSectionError: Section 'phi' already exists