Don't pass along unused btStackAlloc everywhere. The API change might user code (derived classes with the old virtual method are not called anymore)

src/BulletCollision/CollisionDispatch/btConvexConvexAlgorithm.cpp

@@ -373,7 +373,6 @@ void btConvexConvexAlgorithm ::processCollision (const btCollisionObjectWrapper*
 		input.m_maximumDistanceSquared*= input.m_maximumDistanceSquared;
 	}
 
-	input.m_stackAlloc = dispatchInfo.m_stackAllocator;
 	input.m_transformA = body0Wrap->getWorldTransform();
 	input.m_transformB = body1Wrap->getWorldTransform();