Add --log-driver json-file in init-containers.sh

[Pierre-Gilles]

Not urgent, but I'm adding --log-driver json-file \ on the website so the --log-opt max-size=10m \ option work in 100% of the case.

Right now it's not necessary here because Docker use this driver by default, but I'm more afraid for the day where they change this setting in the default installation, and we'll have an ugly error

gladys-pi-gen/gladys/02-init-gladys/files/init-containers.sh

Line 46 in 6f47609

--log-opt max-size=10m \