(#10263) Fix tests on Puppet 2.6.x
(#10263) Fix tests on Puppet 2.6.x

Due to the lack of Puppet::Test::LogCollector class, tests fail on puppet
2.6.x. Instead of just using the class, I'm testing its existance first
and only using it if it exists. Otherwise, I'm going to fall back to 2.6.x
methodology.

This seems to make tests work on 2.6.7 (and up) and 2.7.1 (and up) which is
sufficient for now.

jaakkosipari/puppetlabs-firewall,puppetlabs/puppetlabs-firewall,ianand0204/puppetlabs-firewall