Per thread starting here:

    http://www.open-mpi.org/community/lists/users/2014/01/23327.php

Revert the Fortran mpi module default size to "small", meaning that we
won't provide interfaces for MPI subroutines that take a choice buffer
any more.  The short version is that MPI-3 p610:34-41 disallows it.

This commit simply removes all these subroutines from the build
process (i.e., remove them from nodist_libmpi_usempi_la_SOURCES).
Since MPI-3 actually forbids providing these interfaces, I'll do a
second commit to actually remove all the scripts and associated
Makefile.am junk.

cmr=v1.7.4:reviewer=dgoodell:subject=Remove choice buffer interfaces from Fortran mpi module