Using :load-path without also using :ensure now implies :ensure nil

Fixes https://github.com/jwiegley/use-package/issues/190

etc/USE-PACKAGE-NEWS

@@ -27,6 +27,7 @@
 - Support multiple symbols passed to `:after`, and a mini-DSL using `:all` and
   `:any`.
 - `:mode` and `:interpreter` can now accept `(rx ...)` forms.
+- Using `:load-path` without also using `:ensure` now implies `:ensure nil`.
 - `:bind (:map foo-map ...)` now defers binding in the map until the package
   has been loaded.
 - Print key bindings for keymaps in `describe-personal-keybindings`.

lisp/use-package/use-package.el

@@ -1764,6 +1764,9 @@ this file.  Usage:
                                       (not (memq :defer args)))
                                  (append args '(:demand t))
                                args)))
+                  (when (and (plist-member args* :load-path)
+                             (not (plist-member args* :ensure)))
+                    (plist-put args* :ensure nil))
                   (unless (plist-member args* :init)
                     (plist-put args* :init nil))
                   (unless (plist-member args* :config)