Deprecation of interacting with v1 registries was
started in docker 1.8.3, which added a `--disable-legacy-registry`
flag.
This option was anounced to be the default starting
with docker 17.06, and v1 registries completely
removed in docker 17.12.
This patch updates the default, and disables
interaction with v1 registres by default.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>