bug#12916: 24.2; Completion for "C-x b" does not include current buffer

[Richard Copley <rcopley@gmail.com>]

In older Emacs versions (*), to switch buffer, I could type "C-x b",
followed by a unique prefix of the desired buffer's name, then "TAB
RET". This routine no longer works. Specifically, the completion fails
when the desired buffer is already the current buffer. So before I can
switch, I first have to work out which window is selected and whether
its buffer is the one I want.

In my opinion this was a bad decision, and I think we should go back
to using "B" as the interactive spec for switch-to-buffer. Others
might disagree, so would it be possible to add a custom variable to
control whether the current buffer is included in the list of completions?

(*) (I think the behaviour changed on the trunk in
revisions 86915 and 86916, in April 2008.)

In GNU Emacs 24.2.1 (i386-mingw-nt6.1.7601)
 of 2012-08-29 on MARVIN

Major mode: Lisp Interaction

Recent input:
C-x b * s c r a t c h <tab> <tab> <tab> <tab> C-g
M-x r e p o r t - e m a c s - b u g <return>