Backport cloud-init status --wait to Trusty

[Adam Collard]

`cloud-init status --wait` is the canonical way to wait for cloud-init to finish, so things that rely on it's actions can use it and know that they're complete.

It's hard to write such tooling when the Trusty version of cloud-init does not support the 'status --wait' sub-command.

cloud-init:
  Installed: 0.7.5-0ubuntu1.22
  Candidate: 0.7.5-0ubuntu1.22
  Version table:
 *** 0.7.5-0ubuntu1.22 0
        500 http://archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     0.7.5-0ubuntu1.18 0
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
     0.7.5-0ubuntu1 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

[Chad Smith (chad.smith)]

Should be a faily simple opportunity to backport tooling-only. The CLI is decoupled from the general behavior of cloud-init on clouds and it'd be nice to have both cloud-init collect-logs as well as cloud-init status on earlier LTS than Xenial.

[Chad Smith (chad.smith)]

This changeset is not as low-hanging as I originally expected. Trusty still sits at 0.7.5 which has no cloudinit.cmd module yet which encapsulates the CLI. This makes backporting the CLI a little bit more than a single file backport and a bit more delta for trusty which we may not be super comfortable with.