sanitize extraJDL. See #8420

[cmsdmwmbot]

Jenkins results:

• Python3 Pylint check: succeeded
  • 4 comments to review
• Pycodestyle check: succeeded
  • 50 comments to review

Details at https://cmssdt.cern.ch/dmwm-jenkins/view/All/job/DMWM-CRABServer-PR-test/1995/artifact/artifacts/PullRequestReport.html

[belforte]

pylint complains refer to "tricky" strings in the submission dagAd part which shoud better not be touched. May go away with #8336