Fix error handling in installApp

Pass the `error` object to the error handler, so that we get something meaningful passed through to the client.

Previously:

```
info: Responding to client with error: {"status":1,"value":{"message":"undefined status object"},"sessionId":"0f8c271f-bdeb-4b94-8daa-453da23f3de0"}
```

Now:

```
info: Responding to client with error: {"status":1,"value":{"message":"You can not call installApp for the iOS simulator!"},"sessionId":"cfa7a214-db9a-4b2d-8949-15cb42efa37c"}
```

Deals with issue #2728