Add check for device not found

https://github.com/appium/appium/issues/2995
and note that in this case we also need to short-circuit the method here, so really we want to return with the setTimeout:

```js
return setTimeout(function () {
  this.adb.getDevicesWithRetry(function (err, devices) {
    if (err) return _cb(new Error("Recconect failed, devices are: " + devices));
    _cb(new Error(stderr)); // we've reconnected, so get back into the retry loop
  });
}.bind(this), 1000);
```

this makes sure that the setTimeout is the last thing we do in this run, and we don't inadvertently call the callbacks again