This fix tries to address the issue raised in 24958 where previously
`docker swarm init` will automatically fill in all the default value
(instead of letting swarmkit to handle the default).
This fix update the `swarm init` so that initial value are passed only
when a flag change has been detected.
This fix fixes 24958.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
Better formatting for usage template.
Group commands in usage to management/operation commands.
Remove the word Docker from the description of management commands.
Signed-off-by: Daniel Nephin <dnephin@docker.com>
