Add a classad that tells us whether the slot (and job) are run inside Parrot

[gonzalomerino]

We want to know which slots did not find native CVMFS and are running jobs inside Parrot. Let us have a machine classad that signals that (PYGLIDEIN_PARROT=true?) and add it to the list of classads to be passed to jobs. It will not hurt to have this data in the condor_history along with the jobs.