fixed logging

I'd rather split it into two lines:

```ruby
result = Pkg.ResolvableInstall(pattern, :pattern)
log.info "Pre-select pattern #{pattern}: #{result}"
```

I do not like logging calls with side effects, if you later decide to remove the logging (you find it too verbose) then the side effect will be removed too resulting in a bug...

In this case it's not that obvious as there is just one logging line, but if later there is added some new code around, this can happen quite easily...