Remove use after free and free of uninit value in mainconfig error path

Signed-off-by: Steven Dake <sdake@redhat.com>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>

exec/mainconfig.c

@@ -433,7 +433,6 @@ static int corosync_main_config_set (
 
 parse_error:
 	*error_string = error_reason;
-	free(value);
 
 	return (-1);
 }