Retry connection backoff after 54 tries reconnections every 0 second

[nebularazer]

In reference to the fix in af4e2ec and the corresponding discussions in #37.

When the overflow happens we end up with a reconnection delay of 0ms, which causes a crazy reconnect spam.

I think the second argument to Math.max should be _max as this overflow happens only when we at max retry delay anyways.

return Math.max(Math.min(ms, _max), _max);

[jumperchen]

But, if the overflow doesn't happen, it still uses the _max value, doesn't it?
So we may change it with the following condition.

var temp = Math.min(ms, _max);
return temp <= 0 ? _max : temp;