chore: fixed warning when building with no-default-feature

crates/shadowsocks/src/config.rs

@@ -464,15 +464,15 @@ fn make_derived_key(method: CipherKind, password: &str, enc_key: &mut [u8]) -> R
         if #[cfg(any(feature = "stream-cipher", feature = "aead-cipher"))] {
             let _ = method;
             openssl_bytes_to_key(password.as_bytes(), enc_key);
+
+            Ok(())
         } else {
             // No default implementation.
             let _ = password;
             let _ = enc_key;
             unreachable!("{method} don't know how to make a derived key");
         }
     }
-
-    Ok(())
 }
 
 /// Check if method supports Extended Identity Header