Three things happen:
1) Omar Khadr was involved in terrorist activities (pretty much confirmed)
2) US government kept him illegally, without trial and mistreated him
3) Canadian government failed taking care of one of her citizens

 The last misconduct is rectified. How about the first and second? Is Canadian Government planning to bring charges against a terrorist? Omar Khadr committed   criminal acts against Canadian nation: terrorized coalition forces, which Canada is a part of. Is Canadian Government planning to sue US Government for  their misconduct? Well, peripheries do not bring charges against the  Central Power. But on the other hand, Donald Tramp states that US does not want to be a (or the) Empire any more. May be this is a good time, and it could be a part of US PR campaign to demonstrate her intentions to move away from being the Central Power (Empire).