fix more places in btSoftBody that assume btRigidBody (it wasn't designed to support btCollisionObject/btGhostObject).

Add another 'findActiveObject'

src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp

@@ -344,6 +344,8 @@ int	btDiscreteDynamicsWorld::stepSimulation( btScalar timeStep,int maxSubSteps,
 	if (numSimulationSubSteps)
 	{
 
+		findActiveObjects();
+
 		saveKinematicState(fixedTimeStep);
 
 		applyGravity();