Install ptscotch for MUMPS
ptscotch is a possible dependency of mumps (#11 (closed)). We are installing it from
$ wget https://gforge.inria.fr/frs/download.php/file/38352/scotch_6.1.0.tar.gz
as this is the last version at this point as indicated in https://gforge.inria.fr/frs/?group_id=248
The tarball contains a INSTALL.txt file.