Scheduler-based testing does not allow for changing module envirorment

[rcabell]

When using the WRF-Hydro CI testing framework with the PBSCheyenne scheduler, there is no way to set a custom module environment for jobs, which can make testing different compiler/MPI combinations difficult and/or cause false-negative test failures.

Expected Behavior

Either the existing module environment set up before calling the testing framework should be passed through, or a provision added to support a custom module set

Current Behavior

Jobs submitted to the PBS scheduler pick up the user's default module environment, instead of any potential custom module environment used to compile the model

Possible Solution

Using the -V flag to qsub would pass through the existing environment from the testing framework to the batch job. This is probably the easiest solution, but an additional command-line argument to specify a module set could work too.

Steps to Reproduce (for bugs)

1. Load a compiler and MPI library module other than the user's default (in my case, gnu/mpt with a default of intel/impi)
2. Run the testing framework
3. ???
4. Crash!