Remove overrideable Go-Guerrilla configuration

Change-Id: Ia37618ee99df180faae01e84fcb4129dc69256d2
diff --git a/cmd/hichipbridge/config.sample.json b/cmd/hichipbridge/config.sample.json
index a0ad7d7..90582f3 100644
--- a/cmd/hichipbridge/config.sample.json
+++ b/cmd/hichipbridge/config.sample.json
@@ -2,6 +2,7 @@
     "log_file": "stderr",
     "log_level": "debug",
     "backend_config": {
+        "save_workers_size": 1,
         "log_received_mails": false
     },
     "servers": [{
diff --git a/cmd/hichipbridge/serve.go b/cmd/hichipbridge/serve.go
index b16de0a..17b944e 100644
--- a/cmd/hichipbridge/serve.go
+++ b/cmd/hichipbridge/serve.go
@@ -148,16 +148,6 @@
 		"EMAIL_TOKEN",
 	}
 
-	// Set default configuration (overridable)
-	defaultAppConfig := guerrilla.AppConfig{
-		BackendConfig: backends.BackendConfig{
-			"save_workers_size":  1,
-			"log_received_mails": false,
-		},
-	}
-
-	d.SetConfig(defaultAppConfig)
-
 	// Load in the config.
 	appConfig, err := d.LoadConfig(path)
 	if err != nil {