optimize skynet.error

examples/main.lua

@@ -4,7 +4,7 @@ local sprotoloader = require "sprotoloader"
 local max_client = 64
 
 skynet.start(function()
-	print("Server start")
+	skynet.error("Server start")
 	skynet.uniqueservice("protoloader")
 	local console = skynet.newservice("console")
 	skynet.newservice("debug_console",8000)
@@ -15,7 +15,6 @@ skynet.start(function()
 		maxclient = max_client,
 		nodelay = true,
 	})
-	print("Watchdog listen on ", 8888)
-
+	skynet.error("Watchdog listen on", 8888)
 	skynet.exit()
 end)