[HOTFIX] Fix #855

I remember that Tim has made a code for setting north arrow. So I traced it back, I found this commit that still has the 'north arrow code':
https://github.com/AIFDR/inasafe/blob/8a99a2d13c3876141ca8652c0c00177aa385ee42/safe_qgis/widgets/dock.py#L1904

```
north_arrow_path = settings.value(
            'inasafe/northArrowPath', '', type=str)
        if north_arrow_path != '':
            print_map.set_organisation_logo(north_arrow_path)
```

That code won't work anyway (it sets the organisation_logo not the arrow image)

A commit after that (exactly a commit), that code is gone:
https://github.com/AIFDR/inasafe/blob/b1684ac69978ec95a1c0286391e6342b6dbcdb3c/safe_qgis/widgets/dock.py

The strange thing is if we see this commit diff, that commit does not delete the 'north arrow' code:
https://github.com/AIFDR/inasafe/commit/8a99a2d13c3876141ca8652c0c00177aa385ee42