Support subdirectories when saving places in dired.

* lisp/saveplace.el (toggle-save-place, save-place-to-alist)
(save-places-to-alist, save-place-dired-hook):
Use dired-current-directory instead of dired-directory.
(save-place-dired-hook): Add check for alist to make the new
format future-proof to allow other possible formats.

Fixes: debbugs:19436
Avoid duplicate calls of window-height in with-displayed-buffer-window

* lisp/minibuffer.el (minibuffer-completion-help):
Use shrink-window-if-larger-than-buffer in window-height
when temp-buffer-resize-mode is nil.

* lisp/window.el (with-displayed-buffer-window): Remove window-height
from the action alist in the temp-buffer-window-show call
when window-height is handled explicitly afterwards.

Fixes: debbugs:19355