rtmp-services: Allow service updates to be disabled on *nix

Effectively reverts 8b315186a724f3af59163196db79080ffd26dfcb, as the
cmake referenced in the description has long since been completely
rewritten and replaced.

plugins/rtmp-services/rtmp-services-main.c

@@ -83,7 +83,7 @@ bool obs_module_load(void)
 	proc_handler_add(ph, "void twitch_ingests_refresh(int seconds)",
 			 refresh_callback, NULL);
 
-#if !defined(_WIN32) || defined(ENABLE_SERVICE_UPDATES)
+#if defined(ENABLE_SERVICE_UPDATES)
 	char *local_dir = obs_module_file("");
 	char *cache_dir = obs_module_config_path("");
 	char update_url[128];