epg: Adjust to GnuPG 2.1 key listing change

  
* epg.el (epg--list-keys-1): Ignore fields after the 15th field
(bug#18979).  Reported by Hideki Saito.

Backported from trunk.

lisp/ChangeLog

+2014-11-07  Daiki Ueno  <ueno@gnu.org>
+
+	* epg.el (epg--list-keys-1): Ignore fields after the 15th field
+	(bug#18979).  Reported by Hideki Saito.
+
 2014-10-18  Alan Mackenzie  <acm@muc.de>
 
 	Check that a "macro" found near point-min isn't a ## operator.

lisp/epg.el

@@ -1910,8 +1910,9 @@ This function is for internal use only."
 	      string (match-string 0)
 	      index 0
 	      field 0)
-	(while (eq index
-		   (string-match "\\([^:]+\\)?:" string index))
+	(while (and (< field (length (car keys)))
+		    (eq index
+			(string-match "\\([^:]+\\)?:" string index)))
 	  (setq index (match-end 0))
 	  (aset (car keys) field (match-string 1 string))
 	  (setq field (1+ field))))