GEOS-Chem submod update: Merge PR #2182 (Add #SBATCH -c 1)

This commit informs the GCHP superproject about the following
commits that were pushed to the GitHub geos-chem/geos-chem repository:

874f840a0 Merge PR #2182 (Add #SBATCH -c 1; Allow scheduler "none" in int tests)

This PR adds a hotfix to Harvard Cannon GCHP run scripts and GCHP
integration tests scripts.  GCClassic and GCHP integration tests may now
also use a value of "none" for the scheduler argument.

Signed-off-by: Bob Yantosca <yantosca@seas.harvard.edu>