SSH2: close channel when a timeout occurs

phpseclib/Net/SSH2.php

@@ -3815,6 +3815,7 @@ class Net_SSH2
                     // on windows this returns a "Warning: Invalid CRT parameters detected" error
                     if (!@stream_select($read, $write, $except, $sec, $usec) && !count($read)) {
                         $this->is_timeout = true;
+                        $this->_close_channel($client_channel);
                         return true;
                     }
                     $elapsed = strtok(microtime(), ' ') + strtok('') - $start;