I was first shocked that Mycroft would send Sherlock to his death but now I feel it's part of some bureaucratic maneuvring to keep him out of prison and alive. I don't believe he wants Sherlock to die, he said so in the smoking scene, CAM uses Sherlock as his pressure point and he protected Sherlock from the helicopter.
There are some odd things he does: he seems to know there's somthing in the punch, he arranges Sherlock's exile with the woman whose husband was driven to suicide by CAM, she can't be too sorry that he's dead. Something fishy is going on.
My explanation: Mycroft is desperately trying to be perceived as a psychopath with no soft feelings whatsoever. He is really powerful and has a lot of enemies. His brother is his weak spot and his enemies will exploit that if they find out. That's why he has to be so callous. He pretends that he doesn't care and gives him a death sentence to prove it.
Then, conveniently, Morarty shows up and Mycroft doesn't have to follow through. How nice for him! I find this way too much lucky coincidence for Mycroft so I believe he's behind it. But whether he arranged the film or not, he surely used it to his advantage.