Add HLTMPPU Child Issue to check_log patterns
This pattern will help to catch the case when HLTMPPU child crashes but there's no other error message and the mother process exits with zero. The error message to catch in this case is:
2019-Aug-05 18:53:21,016 WARNING [HLTMPPU::doNannyWork(...) at /builds/atlas-tdaq-software/tdaq-cmake/HLTMPPU/src/HLTMPPU.cxx:1198] Child Issue: "Child pid=9991 exited with signal 9".
Adding this to both the perl and the python check_log version.