Refactor error management in API part

src/model/block.rs

@@ -123,7 +123,7 @@ impl BlockManager {
 			Message::PutBlock(m) => self.write_block(&m.hash, &m.data).await,
 			Message::GetBlock(h) => self.read_block(h).await,
 			Message::NeedBlockQuery(h) => self.need_block(h).await.map(Message::NeedBlockReply),
-			_ => Err(Error::BadRequest(format!("Unexpected RPC message"))),
+			_ => Err(Error::BadRPC(format!("Unexpected RPC message"))),
 		}
 	}