This utility was only used for testing, and to generate a random
suffix for Dockerfiles. As we don't need the same contract as
pkg/stringid.GenerateRandomID() (not allow all-numeric IDs as they
would not be usable for hostnames), we can use a local test-utility,
and local implementation for the random suffix instead.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
