fix windows route delete's missing mask

src/network/tun_win.rs

@@ -789,6 +789,7 @@ pub fn del_route(net: &Ipv4Net, gw: &Ipv4Addr) -> Result<()> {
     let res = Command::new("route")
         .arg("delete")
         .arg(network)
+        .arg("MASK")
         .arg(mask)
         .arg(gw.to_string())
         .output()?;