Make get_early_config even earlier

Also improve the management of X Display and session_t.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/dbus.c

@@ -1024,7 +1024,7 @@ cdbus_process_opts_get(session_t *ps, DBusMessage *msg) {
     return true;
   }
 
-  cdbus_m_opts_get_do(config_file, cdbus_reply_string);
+  cdbus_m_opts_get_stub(config_file, cdbus_reply_string, "Unknown");
   cdbus_m_opts_get_do(write_pid_path, cdbus_reply_string);
   cdbus_m_opts_get_do(mark_wmwin_focused, cdbus_reply_bool);
   cdbus_m_opts_get_do(mark_ovredir_focused, cdbus_reply_bool);