[O-MPI devel] Now require Libtool >= v1.5.16

[Jeff Squyres]

autogen.sh has been updated to now check for Libtool >= v1.5.16.  If 
you need to upgrade your local version of Libtool, here's a link to the 
latest version:

        ftp://ftp.gnu.org/gnu/libtool/libtool-1.5.20.tar.gz
--
{+} Jeff Squyres
{+} The Open MPI Project
{+} http://www.open-mpi.org/