ox-icalendar: Small fix

* lisp/ox-icalendar.el (org-icalendar-export-current-agenda): Add
  missing properties.  Also fix typo for body-only argument.

lisp/ox-icalendar.el

@@ -903,7 +903,7 @@ This function assumes major mode for current buffer is
 			    (buffer-substring
 			     (point) (progn (outline-next-heading) (point)))))))))
 		   (forward-line)))))
-	   'icalendar file)))
+	   'icalendar t '(:ascii-charset utf-8 :ascii-links-to-notes nil))))
     (with-temp-file file
       (insert
        (org-icalendar--vcalendar