Fixed product probing when evaluating rules/rules.xml file

NTH: more readable test:
```
param = "cpe:/o:suse:sles:12,SUSE Linux Enterprise Server 12"
expected_result = {
  "cpeid" => "cpe:/o:suse:sles:12",
  "name" => "SUSE Linux Enterprise Server 12"
}

expect(subject.send(:distro_map, param).to eq(expected_result)
```