[2.0 b3] tag only supports 'nodes' and and not 'machines' or 'controller's

[Andres Rodriguez]

Trying to list all machines with a specific tag, I came across this command:

retcode for maas maas ['tag', 'machines', 'all']: {{{2}}}
stderr for maas maas ['tag', 'machines', 'all']: {{{
usage: /usr/bin/maas maas tag [-h] COMMAND ...

Manage a Tag.

optional arguments:
  -h, --help show this help message and exit

drill down:
  COMMAND
    update-nodes
                Add or remove nodes being associated with this tag.
    read Read a specific Tag.
    update Update a specific Tag.
    rebuild Manually trigger a rebuild the tag <=> node mapping.
    nodes Get the list of nodes that have this tag.
    delete Delete a specific Tag.

Tags are properties that can be associated with a Node and serve as
criteria for selecting and allocating nodes.

A Tag is identified by its name.

argument COMMAND: invalid choice: 'machines' (choose from 'update-nodes', 'read', 'update', 'rebuild', 'nodes', 'delete')
}}}

MAAS should allow the following:

maas <user> tag *machines* <tag_name> # All machines
maas <user> tag *controllers* <tag_name> # all controllers
maas <user> tag *nodes* <tag_name> # all machines, controllers, devices, etc.