WIP #2347 - removed hard-coded mpi.cfg.cores
WIP #2347 - removed hard-coded mpi.cfg.cores

mkeilman/sirepo,radiasoft/sirepo,mkeilman/sirepo,radiasoft/sirepo,mkeilman/sirepo,radiasoft/sirepo,mkeilman/sirepo,radiasoft/sirepo,radiasoft/sirepo