fix #2588 set deploy.mode to warm

src/main/resources/fess_env.properties

@@ -5,7 +5,7 @@
 #                                                                                    Core
 #                                                                                   ======
 # The mode of Lasta Di's smart-deploy, should be cool in production (e.g. hot, cool, warm)
-lasta_di.smart.deploy.mode = hot
+lasta_di.smart.deploy.mode = warm
 
 # Is development environment here? (used for various purpose, you should set false if unknown)
 development.here = true