* lisp/progmodes/python.el (python-shell-calculate-command): Rename

* lisp/progmodes/python.el (python-shell-calculate-command): Rename
from python-shell-parse-command.  Cleanup.
(run-python, run-python-internal): Use it.
(python-shell-calculate-pythonpath): Rename from
python-new-pythonpath.
(python-shell-calculate-process-environment): Use it.
(python-shell-calculate-exec-path): Add comment.

* test/automated/python-tests.el
(python-shell-calculate-process-environment-2): Fix test.
(python-shell-calculate-process-environment-1)
(python-shell-calculate-process-environment-3): Cleanup.