check for cvmfs before starting condor

[dsschult]

We should check for cvmfs before starting condor, since it's basically required for our jobs.

Simple check is:

if [ -e /cvmfs/icecube.opensciencegrid.org/py2-v1/setup.sh ]; then
    CVMFS="true"
fi

Harder is to launch parrot in the else case, and check again.

[briedel]

Would also help with moving condor into cvmfs rather than dealing with tarballs

[gonzalomerino]

Hi David, OSG glideinWMS glideins publish this classad after checking for our repo HAS_CVMFS_icecube_opensciencegrid_org true, or false could we adopt the same one in pyglidein? Gonzalo

[dsschult]

Gonzalo: already done in df26634