player/fetch.rs: fix bug of crash on some song

Crash is caused by the file passed to mp3_duration is a error response
instread of mp3 file because the HOST field in request header does not
match the url.

src/player/fetch.rs

@@ -1,6 +1,6 @@
 use std::io::prelude::*;
 use futures::channel::oneshot::Sender;
-use reqwest::header::{HOST, CACHE_CONTROL, PRAGMA, HeaderMap, UPGRADE_INSECURE_REQUESTS, ACCEPT, ACCEPT_ENCODING, USER_AGENT};
+use reqwest::header::{CACHE_CONTROL, PRAGMA, HeaderMap, UPGRADE_INSECURE_REQUESTS, ACCEPT, ACCEPT_ENCODING, USER_AGENT};
 use reqwest::Method;
 use tempfile::NamedTempFile;
 
@@ -14,7 +14,6 @@ pub async fn fetch_data(url: &str, buffer: NamedTempFile, tx: Sender<String>) ->
     headers.insert(CACHE_CONTROL, "no-cache".parse().unwrap());
     headers.insert(PRAGMA, "no-cache".parse().unwrap());
     headers.insert(UPGRADE_INSECURE_REQUESTS, "1".parse().unwrap());
-    headers.insert(HOST, "m7.music.126.net".parse().unwrap());
     headers.insert(ACCEPT, "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3".parse().unwrap());
     headers.insert(ACCEPT_ENCODING, "gzip,deflate".parse().unwrap());
     headers.insert(