I just installed Open MPI 1.3.1 and found that the following assertion
Assert(version == MPI_VERSION && subversion == MPI_SUBVERSION);
This is an excerpt from pyMPI, which I have been using with Open MPI 1.2.7.
According to mpi.h, MPI_VERSION == 2 and MPI_SUBVERSION == 1, but the
procedure MPI_Get_version returns 2 and 0 for version & subversion
I think this is a quick fix to sync up the mpi.h and get_version.c.