* lisp/progmodes/python.el (python-mode-map): Remove binding for ":".

* lisp/progmodes/python.el (python-mode-map): Remove binding for ":".
(python-indent-electric-colon): Remove command.
(python-indent-post-self-insert-function): Integrate the previous code
of python-indent-electric-colon.  Make it conditional on
electric-indent-mode.
(python-mode): Add ?: to electric-indent-chars.
Move python-indent-post-self-insert-function to the end of
post-self-insert-hook.