Fix in Exercise 4

[4flixt]

When the mpc_solver for the final loop is created, the equality constraints are appended to g, and np.zeros((nx, 1)) are appended to lb_g and ub_g. However, in the loop when the mpc_solver is called, the values given for the lbg and ubg input parameters is simply the scalar 0. lb_g and ub_g are not used in the creation og the mpc_solver either, and I can't find anywhere they are used, and thus wondering about the purpose of them? My guess is that you could have different values on them, and they would correspond to the equality in g, but if I try to pass them as input arguments, I get an error.