fix #1323 eliminate OMPI_ and PMIX_ from environ before exec
fix #1323 eliminate OMPI_ and PMIX_ from environ before exec

h5py is starting MPI but it shouldn't really so this trick is necessary

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