Large MPI job startup hang with mvapich2/2.3 and mvapich2/2.3.1

Resolution: 
Unresolved

We have found that large MPI jobs may hang at startup with mvapich2/2.3 and mvapich/2.3.1 (on any compiler dependency) due to a known bug that has been fixed in release 2.3.2. If users experience this issue, please switch to mvapich2/2.3.2.