Fix bug with exporting table metalines to LaTeX/PDF

* lisp/org-exp.el (org-export-handle-table-metalines): Choose a better
position for checking protectedness.

lisp/org-exp.el

@@ -1691,7 +1691,7 @@ When it is nil, all comments will be removed."
     (while (or (looking-at re)
 	       (re-search-forward re nil t))
       (setq pos (match-beginning 0))
-      (if (get-text-property (point) 'org-protected)
+      (if (get-text-property (match-beginning 1) 'org-protected)
 	  (goto-char (1+ pos))
 	(goto-char (1+ pos))
 	(replace-match "")