Add explicit dyns (#1041)

* Add explicit `dyn`s

* Remove unnecessary lines

src/middleware/normalize.rs

@@ -151,5 +151,4 @@ mod tests {
         let res = block_on(normalize.call(req)).unwrap();
         assert!(res.status().is_success());
     }
-
 }

src/resource.rs

@@ -763,5 +763,4 @@ mod tests {
         let resp = call_service(&mut srv, req);
         assert_eq!(resp.status(), StatusCode::NO_CONTENT);
     }
-
 }

src/types/form.rs

@@ -482,5 +482,4 @@ mod tests {
         use crate::responder::tests::BodyTest;
         assert_eq!(resp.body().bin_ref(), b"hello=world&counter=123");
     }
-
 }