sh-i18n--envsubst: do not crash when no arguments are given

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sh-i18n--envsubst.c

@@ -74,6 +74,7 @@ main (int argc, char *argv[])
 	{
 	case 1:
 	  error ("we won't substitute all variables on stdin for you");
+	  break;
 	  /*
 	  all_variables = 1;
       subst_from_stdin ();