[usb-moded] Do not do post-sync after mode setting error.

There is no point in running the post-sync if the mode setting failed.
So we skip it in that case (also makes sure that the services are not
active in the failure case)

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>

src/usb_moded-modesetting.c

@@ -445,7 +445,8 @@ int set_dynamic_mode(void)
   if(data->nat || data->dhcp_server)
 	ret = usb_network_set_up_dhcpd(data);
 
-  if(data->appsync)
+  /* no need to execute the post sync if there was an error setting the mode */
+  if(data->appsync && !ret)
 	activate_sync_post(data->mode_name);
 
   if(ret)