Uncomment dependencies previously disallowed by concretizer (#9942)

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

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

var/spack/repos/builtin/packages/py-enum34/package.py

var/spack/repos/builtin/packages/py-flake8/package.py

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

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

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

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

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

...spack/repos/builtin/packages/py-singledispatch/package.py

...spack/repos/builtin/packages/py-slurm-pipeline/package.py

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

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

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