Support "sbatch [full-path]/lenkf.j

[gmao-rreichle]

After setting up GEOSldas, the sbatch job must currently be submitted from the ./run directory, that is:

cd [exp-path]/run
sbatch lenkf.j

We should make it possible to execute sbatch from anywhere, that is:
sbatch [exp-path]/run/lenkf.j

Per a suggestion from Matt, this can be probably done by adding something like the following line into lenkf.j:
#SBATCH --chdir=[exp-path]/run

Not sure what the corresponding command for PBS would be, but chances are there's something similar.

[gmao-rreichle]

closing (addressed with #745)