GitLab

**Description**
As MPI can not be inited twice in one same process (by py and c)
Also, MPI env initialized by mpi4py can not be reused in C env

To avoid MPI init issue introduced from mpi4py, rewrite gen_ibstat_file function to generate ibstat file leveraged by pssh

**Major Revision**
- Rewrite gen_ibstat_file function to generate ibstat file leveraged by pssh

**Minor Revision**
- Remove mpi4py dependency

Tested the functionality of topo-aware on 36 nodes cluster