Tone down spawn of Shocker brute

People was complaining about shocker brute being to common even outside power station, if I understand the code correctly, this should tone it down a bit.
Yeah, this is why I wish folks would expressly write out where they have things spawn.  Shocker Brutes are pretty out of place in a random house.or grocery (or pharmacy).  I'd look for them in labs or power stations.  Maybe the hospital.