Intel MPI build fails to import MPI

[cfrontin]

Running with Intel MPI on NREL's Kestrel, MPI is set to None because none of the variable formats here are used by the Intel MPI build.

I have:

>>> for name in os.environ.keys():
...   if "MPI" in name:
...     print(name)
... 
I_MPI_PMI_LIBRARY
I_MPI_PMI
MPICC
INTEL_ONEAPI_COMPILERS_ROOT_DIR
INTEL_ONEAPI_MPI_ROOT_DIR
I_MPI_ROOT

so it's probably adequate to include I_MPI_ROOT to the list?

A current workaround is to create a dummy env variable (e.g. export MPICH_I_MPI_DUMMY=1) that satisfies the requirements, allowing mpi4py.MPI to get used correctly in an intel build.

[gbarter]

@cfrontin - Keep open or close?

[cfrontin]

This change works locally for me- I defer to you on whether it should go into the repo or not?

[cfrontin]

I do think some folks are running serial exclsusively on Kestrel because of this as of two weeks ago

[gbarter]

Should be resolved with this commit.