bug#10958: 24.0.94; cycling completion bug

[Leo]

Cycle completion omits some candidates.

1. emacs -q
2. (setq completion-cycle-threshold 4)
3. (setq tab-always-indent 'complete)
4. In a new emacs-lisp-mode buffer, type `defm TAB'. It completes to
   defmath and says sole completion. `defmacro' is completely ignored.

You can also try to complete `push-', push-button is ignored and only
push-mark and push-mark-command are in the cycling.

Leo