{input,storage}/curl: set CURLOPT_HTTPAUTH=CURLAUTH_BASIC

With the default value CURLAUTH_ANY, libcurl needs to probe for
authentication methods first, and only the second request will have an
Authorization header.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1155

src/input/plugins/CurlInputPlugin.cxx

@@ -421,6 +421,10 @@ CurlInputStream::InitEasy()
 	request->SetOption(CURLOPT_MAXREDIRS, 5L);
 	request->SetOption(CURLOPT_FAILONERROR, 1L);
 
+	/* this option eliminates the probe request when
+	   username/password are specified */
+	request->SetOption(CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
+
 	if (proxy != nullptr)
 		request->SetOption(CURLOPT_PROXY, proxy);