Improve logParser behaviour when jO is not found [skip modfiles]

If a jO was renamed the logParser would crash with the cryptic message

RuntimeError: Unknown format of jO file: 
Should look something like ./421xxx/421001/mc.Sherpa_Example1.py

Now it will crash like this:

RuntimeError: ERROR: mc.PowhegPythia8_A14_ttbar_hdamp258p75_nonallhad.py jobOptions not found in git!

This happened in Serena's tests since she was using a file which had a non-acceptable name, so the check_jo_consistency CI job would fail.

At least it's good that the machinery does not allow simple renamings of files without rerunning athena, so this is just a cosmetic change.