Fix undefined foreman_url error on EL6

I don't know why exactly this is causing a problem, as in theory it's valid.  Unit tests and little examples I create seem to be fine.

However, reality differs: <pre>Jul 29 14:58:29 localhost puppet-master[21334]: Report processor failed: undefined local variable or method `foreman_url' for #<Puppet::Transaction::Report:0x7f7005f7f6d0></pre>