gnu: pytest-mock: remove needless propagated input "python-py".

This is not listed as an requirement and is already propagated by
python-pytest.

* gnu/packages/python.scm (python-pytest-mock, python2-pytest-mock):
  [propagated-inputs]: Remove python-py.

gnu: python-testscenarios: remove needless input "mimetools".

This does not occur in the source.

* gnu/packages/python.scm (python-testscenarios, python2-testscenarios)
  [propagated-inputs]: Remove python-mimeparse.

gnu: python-setuptools: remove pre-built binaries from source.

These are used to build self-extracting installers for Windows.

* gnu/packages/python.scm (python-setuptools, python2-setuptools) [source]:
  Add snippet to delete *.exe files.

gnu: python-pytest-xdist: Remove needless input python-apipkg.

* gnu/packages/python.scm (python-pytest-xdist): Remove input
  python-apipkg.

gnu: python-subunit, python-testrepository: Fix inputs

* gnu/packages/python.scm (python-subunit, python2-subunit):
  [propagated-inputs]:: Add python-extras, remove python-testtools, move
  python-testscenarios to [native-inputs].  (python-testrepository,
  python2-testrepository): [native-inputs] move python-fixtures and
  python-subunit to [propagated-inputs]

gnu: python-scripttest: Correct inputs.

python-pytest is only required for testing, not at run-time.

* gnu/packages/python.scm (python-singledispatch, python2-singledispatch):
  [propagated-inputs] Move python-pytest to [native-inputs].

gnu: python-pandas: Fix build.

* gnu/packages/python.scm (python-pandas): Add python-cython to
  native-inputs.

gnu: openstack: Correct inputs.

* gnu/packages/openstack.scm (python-os-testr) Propagate input
  python-subunit, change all other inputs to native-inputs.
  (python-mox3): Remove needless input python-six.
  (python-stevedore, python-requests-mock): Move python-pbr to
  native-inputs.

gnu: thefuck: Fix build.

Requires setuptools >= 17.1 due to some features used, while our
python currently only includes 12.0.

* gnu/packages/admin.scm (thefuck): Add setuptools to native-inputs.

gnu: vdirsyncer: Fix build by setting correct PYTHONPATH.

For thus, use add-installed-pythonpath.

* gnu/packages/dav.scm (vdirsyncer): set PYTHONPATH using
  add-installed-pythonpath.

gnu: python-ipython: Fix build.

* gnu/packages/python.scm (python-ipython, python2-ipython) [check,
  install-doc] set PYTHONPATH prior to running tests.

gnu: python-scipy: Fix build.

* gnu/packages/python.scm (python-scipy) Use add-installed-pythonpath.  Add
  dummy newlines character to string to make emacs happy.

gnu: python-matplotlib: Fix build.

* gnu/packages/python.scm (python-matplotlib, python2-matplotlib): Correct
  inputs. [install-doc] set PYTHONPATH prior to building docs.

gnu: python-numpy-bootstrap, python-numpy: Fix build.

* gnu/packages/python.scm (python-numpy-bootstrap): Correct inputs, use
  modify-phases, add dummy newlines character to string to make emacs happy,
  set PYTHONPATH prior to running tests. (python-numpy): propagate inputs, set
  PYTHONPATH prior to building docs.

gnu: python-fonttools: Remove intervening directory in site-packges.

* gnu/packages/python.scm (python-fonttools): Add phase patch-setuppy.

gnu: python2-pysnptools: Correct inputs.

dateutil, pytz, and six do not occur in the code.

Remove python-dateutil, python-pytz, python-six from inputs;
Move python-cython to native-inputs; move python-pandas to
propagated-inputs.

gnu: python-zope-testing: Remove needless input.

* gnu/packages.python.scm (python-zope-testing): Remove
  python-zope-interface from native-imports.

gnu: python-zope-schema: Add missing inputs.

* gnu/packages.python.scm (python-zope-schema): Add python-coverage and
  python-nose to native-inputs.

gnu: python-pytest-flakes: Fix build.

* python.scm (python-pytest-flakes): Set PYTHONPATH prior to running tests.

gnu: python-pillow: Fix build.

* gnu/packages/python.scm (python-pillow)[check-installed]: Add
  installed site-package to PYTHONPATH.