Fixes Infested Hellhound so first time infestation gives corruption and sets flag

If PC is first infected not by the worms but by the infested hellhound,
they weren't getting the corruption increase nor was the "has been
infested" flag being set.
Added flags import so fix compiles
Merge pull request #457 from wyvvern/master

Fixes Infested Hellhound so first time infestation gives corruption and ...