Fix launching work directly (not via Slurm)

Description

The --no-cluster-job option was failing to even start jobs. Closes #58.

How Has This Been Tested?

Launched on max-exfl-display:

xfel-calibrate AGIPD CORRECT \
    --in-folder /gpfs/exfel/exp/SPB/202131/p900230/raw --run 174 \
    --out-folder /gpfs/exfel/data/scratch/kluyvert/agipd-calib-900230-174-direct \
    --karabo-id SPB_DET_AGIPD1M-1 --karabo-id-control SPB_IRU_AGIPD1M1 --karabo-da-control AGIPD1MCTRL00 \
    --modules 0 --sequences 0 --no-cluster-job

I let this run until it saved the first HDF5 output files, and then cancelled it (Ctrl-C) so as not to hog the login node. Before these changes, it was failing to even start running the notebooks.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the code style of this project.

Reviewers

@ahmedk @danilevc