The `ValidateHost` option was introduced in [moby@1ba1138] to be used
as validation func for the `--host` flag on the daemon in and CLI in
[moby@5e3f6e7], but is no longer used since [cli@6f61cf0]. which added
support for `ssh://` connections, and required validation elsewhere.
[moby@1ba1138]: 1ba11384bf
[moby@5e3f6e7]: 5e3f6e7023
[cli@6f61cf0]: 6f61cf053a
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>