I recently found a better solution to the problem, which is to run the command:
sudo aa-clickhook -f
My old solution is below:
I had the same issue. The only thing I found which made it possible to use docker again on snappy core, was to remove and reinstall the docker framework using the commands:
sudo snappy remove docker
sudo snappy install docker
At that point I was able to run docker commands without incident. I found that my docker images were still available to me, and the ones started with the flag
--restart always automatically restarted when the docker framework was reinstalled.