org-colview: Do not choke when updating a special property

* lisp/org-colview.el (org-columns--compute-spec): Do not update
special properties, which are not set through property drawers.

Reported-by: Nick Dokos <ndokos@gmail.com>
<http://lists.gnu.org/r/emacs-orgmode/2021-04/msg00135.html>

lisp/org-colview.el

@@ -1167,7 +1167,12 @@ properties drawers."
 	 (printf (nth 4 spec))
 	 (operator (nth 3 spec))
 	 (collect (and operator (org-columns--collect operator)))
-	 (summarize (and operator (org-columns--summarize operator))))
+	 (summarize (and operator (org-columns--summarize operator)))
+         ;; Special properties are not set in a property drawer, and
+         ;; therefore should not be updated.
+         (update
+          (and update
+               (not (member property org-special-properties)))))
     (org-with-wide-buffer
      ;; Find the region to compute.
      (goto-char org-columns-top-level-marker)