Prefer setq-local in python.el

Prefer setq-local in python.el

* lisp/progmodes/python.el: Require Emacs 24.2 instead of 24.1.
(python-indent-guess-indent-offset)
(python-shell-font-lock-with-font-lock-buffer)
(python-shell-font-lock-turn-on)
(python-shell-font-lock-turn-off, python-shell-font-lock-toggle)
(python-shell-comint-watch-for-first-prompt-output-filter)
(inferior-python-mode, python-shell-completion-native-turn-off)
(python-shell-completion-native-turn-on)
(python-pdbtrack-comint-output-filter-function, python-mode):
Prefer setq-local.