Remove mattermost folder (just a git clone, not relevant here

mattermost/.travis.yml

mattermost/Dockerrun.aws.json

mattermost/LICENSE

mattermost/README.aws.md

mattermost/README.md

mattermost/app/Dockerfile

mattermost/app/config.template.json

mattermost/app/docker-entry.sh

mattermost/contrib/kubernetes/README.md

mattermost/contrib/kubernetes/mattermost.deployment.yaml

mattermost/contrib/kubernetes/mattermost.secret.yaml

mattermost/contrib/kubernetes/mattermost.svc.yaml

mattermost/db/Dockerfile

mattermost/db/docker-entrypoint1.sh

mattermost/db/make_db.sh

mattermost/db/setup-wale.sh

mattermost/docker-compose-v1.yml

mattermost/docker-compose.yml

mattermost/web/Dockerfile

mattermost/web/docker-entry.sh