VOL-4284 simplify command line arg specification

Change-Id: Icc96dbf8ef1c06a4976c54fa53ce79f55f715e6a
diff --git a/rw_core/main.go b/rw_core/main.go
index 281756d..9cc1bdc 100644
--- a/rw_core/main.go
+++ b/rw_core/main.go
@@ -74,8 +74,8 @@
 
 	ctx := context.Background()
 
-	cf := config.NewRWCoreFlags()
-	cf.ParseCommandArguments()
+	cf := &config.RWCoreFlags{}
+	cf.ParseCommandArguments(os.Args[1:])
 
 	// Set the instance ID as the hostname
 	var instanceID string