Remove fog-brightbox, radosgw, sakuracloud, softlayer dependencies

Patches are maintained in https://github.com/theforeman/fog/commits/v1.24.0-simplify

---

This will greatly simplify fog updates.  fog 1.25.0 (which is shortly to be merged to core) adds another seven packages, which I'm beginning to lose patience with, so let's just ignore ones we don't need.

The new %check section ensures the patches I'm applying will work reliably, which was a problem last time (as patching the gemspec can be messy).