Collect log to diagnose CVMFS issues

[mambelli]

Is your feature request related to a problem? Please describe.
CVMFS allows to collect information when something goes wrong:

attr -g logbuffer /cvmfs/<repo>|tail -50

This can collect info on what went wrong. To run after the Glidein tests if they failed, and after the job if it failed because of CVMFS

Describe the solution you'd like
This would allow us to collect logs. Glideins could send them to the Factory for troubleshooting

Describe alternatives you've considered
NA

Info (please complete the following information):

• Priority: medium
• Stakeholders:
• Components: glidein

Additional context
Dave suggested this. Fermilab will add it to the Jobsub wrapper

[shreyb]

Regarding the additional context: this is the (currently open) PR in the jobsub project to collect CVMFS logs: fermitools/jobsub_lite#489