conn: clear features support on connection reset

Features may be changed when client reconnects.

src/conn.c

@@ -1222,6 +1222,10 @@ static void _conn_reset(xmpp_conn_t * const conn)
     conn->tls_failed = 0;
     conn->error = 0;
 
+    conn->tls_support = 0;
+    conn->bind_required = 0;
+    conn->session_required = 0;
+
     handler_system_delete_all(conn);
 }