bug#2648: 23.0.60; remove C-c ` from rcirc track minor mode

[Leo]

Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the emacs-pretest-bug@gnu.org mailing list.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

rcirc track mode defines the following keys.

(define-key rcirc-track-minor-mode-map (kbd "C-c `") 'rcirc-next-active-buffer)
(define-key rcirc-track-minor-mode-map (kbd "C-c C-@") 
'rcirc-next-active-buffer)
(define-key rcirc-track-minor-mode-map (kbd "C-c C-SPC") 
'rcirc-next-active-buffer)

When this mode is enabled, those keys become GLOBAL and therefore can
easily step on bindings from other packages. One of them is AUCTeX.

I think it is entirely redundant to bind 'C-c `'. I'd propose this key
be removed when emacs is released. Otherwise it will confuse AUCTeX
users. Whenever there's an error, AUCTeX will ask users to type C-c ` to
get to the error, but instead this key will run
rcirc-next-active-buffer.