Bail out if metrics and daemonization are enabled simultaneously

src/main.rs

@@ -485,6 +485,9 @@ fn bind_listeners(
 }
 
 fn privdrop(config: &Config) -> Result<(), Error> {
+    if config.metrics.is_some() {
+        bail!("Metrics are incompatible with daemonization - set 'daemonize = false' in the configuration file if you need metrics.");
+    }
     let mut pd = PrivDrop::default();
     if let Some(user) = &config.user {
         pd = pd.user(user);