Fix the logviewer

```
15:27 < jpommerening> Hey if anyone cares, the logviewer directive in the current master is broken (or seems to be?)
15:27 < jpommerening> Fix'd it here: https://github.com/jpommerening/buildbot/tree/fix-www-logviewer
15:27 < jpommerening> Gotta go now, took me longer than expected and now I'm late
15:27 < jpommerening> byeeee
```
@tardyp