GEOS-Chem submod update: Merge PR #2207 (Fix bug for SLP & TROPP scal…

…ing)

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

2bcd8bb93 Fix bug for SLP and TROPP scaling

This PR fixes incorrect scale factors for SLP and TROPP in GCHP rundir
creation with GEOS-FP or GEOS-IT met data.

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