[#200] Add tests for --limit-burst
[#200] Add tests for --limit-burst

Both explicit (when a `:burst` parameter or `--limit-burst` argument is
present) and implicit (when neither are specified but `:limit` or `--limit`
are present and the default burst is `5`).

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