This change makes the etcd package compatible with the existing Go
ecosystem for module versioning.
Used this tool to update package imports:
https://github.com/KSubedi/gomove
This commit adds a feature for creating a user without password. The
purpose of the feature is reducing attack surface by configuring bad
passwords (CN based auth will be allowed for the user).
The feature can be used with `--no-password` of `etcdctl user add`
command.
Fix https://github.com/coreos/etcd/issues/9590
