bug#12488: 24.2.50; vc-delete-file and vc-rename-file should default to the current buffer's file

[Chong Yidong]

Dmitry Gutov <dgutov@yandex.ru> writes:

> +Default to the current buffer's file name if it's under version control."

> +OLD defaults to the current buffer's file name if it's under version
>  control."

These seem to imply that the current buffer's name is always used if
it's under version control, rather than simply being the default for
reading the file name.  It should instead say something like "If called
interactively, read FILE, defaulting to ..."

Otherwise the patch looks OK for the trunk.  Thanks.