* lisp/mouse.el: Fix mouse-1-clock-follows-mouse = double

* lisp/mouse.el: Fix mouse-1-clock-follows-mouse = double

This functionality was broken by commit 3d5e31eceb9dc1fb62b2b2,
the problem being that we end up considering as distinct the events
`down-double-mouse-1` and `double-down-mouse-1`.

Reported by Eyal Soha <eyalsoha@gmail.com>

(mouse--click-1-maybe-follows-link): Make sure the last element of
the list passed to `event-convert-list` is indeed a "basic" event.