sexp-conv: Fail with an error message for unexpected ']' characters.

Fixes crash reported by Hanno Böck.

ChangeLog

+2016-02-16  Niels Möller  <nisse@lysator.liu.se>
+
+	* tools/parse.c (sexp_parse): Fail with an error message for
+	unexpected ']' characters. Fixes crash reported by Hanno Böck.
+	Also handle SEXP_DISPLAY (internal error) explicitly, without a
+	default clause.
+
 2016-01-28  Niels Möller  <nisse@lysator.liu.se>
 
 	* Released nettle-3.2.

tools/parse.c

@@ -165,7 +165,10 @@ sexp_parse(struct sexp_parser *parser,
 	case SEXP_CODING_END:
 	  die("Unexpected end of transport encoding.\n");
 	  
-	default:
+	case SEXP_DISPLAY_END:
+	  die("Unexpected end of display tag.\n");
+
+	case SEXP_DISPLAY:
 	  /* Internal error. */
 	  abort();
 	}