fix 1540 and experimental SSH server support

conf/app.ini

@@ -48,6 +48,8 @@ HTTP_ADDR =
 HTTP_PORT = 3000
 ; Disable SSH feature when not available
 DISABLE_SSH = false
+; Whether use builtin SSH server or not.
+START_SSH_SERVER = false
 SSH_PORT = 22
 ; Disable CDN even in "prod" mode
 OFFLINE_MODE = false