This utility was only used for a single test, and it was very limited
in functionality as it only allowed for a certain error-string to be
matched.
Let's change it into a more generic function; a helper that allows a
container to be created from a `TestContainerConfig` (which can be
constructed using `NewTestConfig`) and that returns the response from
client.ContainerCreate(), so that any result from that can be tested,
leaving it up to the test to check the results.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
74feadacf8