Support alternative Xcode6 pref plist path

With Xcode6 user preferences have paths similar to:

```
/Users/krukow/Library/Developer/CoreSimulator/Devices/0181D092-6792-4358-9B70-9348A7DC8061/data/Library/Preferences/com.lesspainful.example.LPSimpleExample.plist
```

we need to support this for simulator tests.