This example was mounting `/dev/zero` as `/dev/nulo` inside the container.
The `nulo` name was intended to be a "made up / custom" name, but various
readers thought it to be a typo for `/dev/null`.
This patch updates the example to use `/dev/foobar` as name, which should
make it more clear that it's a custom name.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit aea2a8c410)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>