Replace use of get_param with param

This has been changed on Rocket master

src/fairing.rs

@@ -26,7 +26,7 @@ impl rocket::handler::Handler for FairingErrorRoute {
         _: rocket::Data,
     ) -> rocket::handler::Outcome<'r> {
         let status = request
-            .get_param::<u16>(0)
+            .param::<u16>(0)
             .unwrap_or(Ok(0))
             .unwrap_or_else(|e| {
                 error_!("Fairing Error Handling Route error: {:?}", e);