(PUP-3378) Don't require puppet resource service output to be the same

Previously, the acceptance test would execute puppet resource service
twice, and compare the output to ensure puppet did not change the state
of the system. This was done because in the past the init service
provider would invoke the status command on all scripts in /etc/init.d,
including /etc/init.d/reboot.sh, which would unconditionally reboot the
system[1]

However, this test is not reliable as some platforms like fedora 19 &
20 have services that change state between the two puppet runs, e.g.
NetworkManager-dispatcher.service, and this behavior is unrelated to
puppet.

This commit removes the requirement that the puppet resource service
command be identical. We continue to execute puppet resource service
twice and compare the output of the ssh(d) service. We also have specs
to ensure that the init service's instances method excludes dangerous
scripts.

This commit also changes the test to use beaker's puppet DSL method,
which is the preferred way of executing puppet in acceptance tests.

[1] http://projects.puppetlabs.com/issues/14615

Paired-with: Eric Thompson <erict@puppetlabs.com>