Remove XML processing code in Orion logic

[fgalan]

XML support in Orion was removed in March 2016 (Orion 1.0.0 release) but it seems PEP stills has logic to deal with it.

XML test has been removed in PR #523 but the code that process it doesn't have been removed. Thus, a -1.4% drop has happened in that PR

I guess once the XML code gets removed the coverage will raise again.