bug#9419: 24.0.50; C-x k deletes the entire frame instead of switching to another buffer

[martin rudalics <rudalics@gmx.at>]

 > However, this use case looks inconsistent, or maybe I don't understand
 > the intended behavior:
 >
 >   emacs -Q
 >   C-x 5 b foo RET
 >
 > then in the new frame:
 >
 >   C-x b bar RET
 >   C-x b foo RET
 >   C-x k RET      (kills the foo buffer and shows bar)
 >   C-x k RET      (kills the bar buffer and shows *scratch*)
 >
 > My understanding of the intended behavior is that since foo and bar
 > are the only 2 buffers in that frame's buffer list, the frame should
 > be deleted after the last one of them is deleted.  But in fact the
 > frame stays alive and shows *scratch*.
 >
 > If I kill the buffers in the reverse order, i.e. bar first and then
 > foo, the frame does get deleted when foo is killed.

I hopefully made these cases consistent now.  In addition, the option
`window-auto-delete' can be used to tune down auto-deletion if wanted.

martin