Don't manage puppetmaster/puppetserver services that aren't present

Under Debian or Ubuntu, the Puppet service providers throw errors for unknown
services, so just leave them unmanaged by default.

--

Apologies, I think this is fixed now.  I've tested it under Ubuntu 14.04 and it seems OK.

Nightly test failure: http://ci.theforeman.org/job/systest_foreman/3418/console

<pre>
# [ERROR 2014-09-25 09:58:52 verbose]  /Stage[main]/Puppet::Server::Service/Service[puppetserver]: Could not evaluate: Could not find init script for 'puppetserver'
# [ INFO 2014-09-25 09:58:52 verbose] /usr/lib/ruby/vendor_ruby/puppet/provider/service/init.rb:138:in `search'
# [ INFO 2014-09-25 09:58:52 verbose] /usr/lib/ruby/vendor_ruby/puppet/provider/service/init.rb:102:in `initscript'
# [ INFO 2014-09-25 09:58:52 verbose] /usr/lib/ruby/vendor_ruby/puppet/provider/service/init.rb:159:in `statuscmd'
# [ INFO 2014-09-25 09:58:52 verbose] /usr/lib/ruby/vendor_ruby/puppet/provider/service/base.rb:41:in `status'
# [ INFO 2014-09-25 09:58:52 verbose] /usr/lib/ruby/vendor_ruby/puppet/type/service.rb:90:in `retrieve'
# [ INFO 2014-09-25 09:58:52 verbose] /usr/lib/ruby/vendor_ruby/puppet/type.rb:1048:in `retrieve'
</pre>