* helm-files.el (helm-find-files-get-candidates): Enable auto update at third char.
(helm-ff--transform-pattern-for-completion): Start concating earlier at second char.
* helm-files.el (helm-ff-auto-update--state): removed.
(helm-ff-toggle-auto-update): Don't use it.
(helm-ff--deleting-char-backward): new flag.
(helm-ff-delete-char-backward,
helm-ff-delete-char-backward--exit-fn): Use it.
(helm-ff-update-when-only-one-matched): Don't allow auto updating when deleting backward.
(helm-find-files-get-candidates): Set path-namedir after maybe setting auto update.