Rename some call sites for read_headers.

Fixes tests.

src/test/redirect.rs

@@ -97,7 +97,7 @@ fn redirect_host() {
     // of example.invalid. We can probably do better by, e.g.
     // overriding the resolver.
     let srv = TestServer::new(|mut stream: TcpStream| -> io::Result<()> {
-        testserver::read_headers(&stream);
+        testserver::read_request(&stream);
         write!(stream, "HTTP/1.1 302 Found\r\n")?;
         write!(stream, "Location: http://example.invalid/\r\n")?;
         write!(stream, "\r\n")?;