Update Nullkiller.cpp

Removed unused variable.

AI/Nullkiller/Engine/Nullkiller.cpp

@@ -349,7 +349,6 @@ void Nullkiller::makeTurn()
 	boost::lock_guard<boost::mutex> sharedStorageLock(AISharedStorage::locker);
 
 	const int MAX_DEPTH = 10;
-	const float FAST_TASK_MINIMAL_PRIORITY = 0.7f;
 
 	float totalHeroStrength = 0;
 	int totalTownLevel = 0;