org-protocol: Fix URL handling

* lisp/org-protocol.el (org-protocol-parse-parameters): Un-escape
  extracted link as it is url-encoded externally.

Reported-by: Pierre Téchoueyres <pierre.techoueyres@free.fr>
<http://lists.gnu.org/r/emacs-orgmode/2019-03/msg00081.html>

lisp/org-protocol.el

@@ -381,7 +381,7 @@ If INFO is already a property list, return it unchanged."
 	  (while data
 	    (setq result
 		  (append result
-			  (list (pop data) (pop data)))))
+			  (list (pop data) (org-link-unescape (pop data))))))
 	  result)
       (let ((data (org-protocol-split-data info t org-protocol-data-separator)))
 	(if default-order