Call install_ methods only once in spec_helper_acceptance

install_puppet already installs puppet on every host. Remove code that
loops over the host array and calls install_puppet for each host in a
multi-host configuration.
`install_pe` and `install_puppet` already have a `hosts.each` loop, so we don't want to do this https://github.com/puppetlabs/beaker/blob/master/lib/beaker/dsl/install_utils.rb#L812