Per http://www.open-mpi.org/community/lists/devel/2014/07/15083.php,
update liboshmem_so_version to 3:0:0 (not 4:0:0, as suggested in the
mail -- the prior version number was 2:0:1).
Remove all comments explaining why version numbers were changed; we
seem to be good-to-go for 1.8.2.