Remove docker.io references of the redis images.

[rafaelvzago]

./east-crs/redis-east.yaml:        image: redis
./east-crs/redis-east.yaml:        image: redis
./north-crs/redis-north.yaml:        image: redis
./north-crs/redis-north.yaml:        image: redis
./west-crs/redis-west.yaml:        image: redis
./west-crs/redis-west.yaml:        image: redis