The install breaks down when trying to fetch matio:
==> Installing matio
==> Fetching http://downloads.sourceforge.net/project/matio/matio/1.5.9/matio-1.5.9.tar.gz
curl: (22) The requested URL returned error: 503 Service Unavailable
==> Fetching from http://downloads.sourceforge.net/project/matio/matio/1.5.9/matio-1.5.9.tar.gz
failed.
==> Error: FetchError: All fetchers failed for matio-1.5.9-nhx6evruhcv7mdg63aws2kyabwenz4hi

If I manually change this in var/spack/repos/builtin/packages/matio/package.py to use https://github.com/tbeu/matio/releases instead of sourceforge, then the install works for matio, but then breaks for boost:
==> Installing boost
==> Fetching http://downloads.sourceforge.net/project/boost/boost/1.63.0/boost_1_63_0.tar.bz2
curl: (22) The requested URL returned error: 503 Service Unavailable
==> Fetching from http://downloads.sourceforge.net/project/boost/boost/1.63.0/boost_1_63_0.tar.bz2 failed.
==> Could not determine url from list_url.
==> Error: FetchError: All fetchers failed for boost-1.63.0-cvwlpzyrr6ltgo3zadtaegwqvrkcudga

I do not know another URL besides sourceforge to use for boost.