(uniquify-managed): Don't defvar.

(uniquify-managed): Don't defvar.
(desktop-buffer-info): Use `uniquify-buffer-base-name', not `uniquify-managed'.
Return also the buffer's base name.
(desktop-save): When saving the buffer info, filter out the base name, and save
it as buffer name if the buffer is managed by uniquify.
(uniquify-item-base): Don't declare; not called anymore.