Fix deptype of various dependencies on Python packages (#3486)

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

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

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

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

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

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

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

var/spack/repos/builtin/packages/py-h5py/package.py

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

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

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

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

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

...ack/repos/builtin/packages/py-scientificpython/package.py

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

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

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

var/spack/repos/builtin/packages/py-unittest2/package.py

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

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