hammer host update --puppet-class-ids is now used for associations

Since https://github.com/theforeman/hammer-cli-foreman/pull/157, the argument
has changed from --puppetclass-ids to --puppet-class-ids.

Looks up the argument name from help output as it's hard to judge which
version of Hammer is being used.
Trivial improvement: ```awk '/class-ids/ {print $1}'```