Remove `all` from `update-node-metadata`

The `all` parameter was previously not functional. It was not mentioned in
the API.md document. It was declared as a valid boolean parameter, but had no
effect on the execution of the command. This removes that superfluous
parameter.

Fixes https://tickets.puppetlabs.com/browse/RAZOR-364
Maybe add: This parameter should have never been accepted by the command, and had no effect