This snippet was added in [docker@38ec5d8][1]. The intent was to indicate
that an empty value is equivalent to passing "default" as value. However,
passing the `--isolation` flag _without a value_ (i.e., no `=` specified)
will fail in many cases, as any string after it will be parsed as value
(e.g. `docker run --isolation busybox` would consider `busybox` as value).
This patch removes these lines as they add more confusion than addressing.
[1]: 38ec5d86a3
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
