Merge branch 'features/blas-lapack-hardening' into develop

lib/spack/llnl/util/filesystem.py

lib/spack/spack/build_environment.py

lib/spack/spack/package.py

var/spack/repos/builtin/packages/netlib-lapack/package.py

var/spack/repos/builtin/packages/openblas/package.py

var/spack/repos/builtin/packages/py-scipy/package.py