[v6r11] Remove systemConfig again

In this commit the Job systemConfig variable is back, it was removed a few commits before that.
https://github.com/DIRACGrid/DIRAC/commit/54698cbc7c1a914ecfb671fe1d200102a30e932b#diff-5a3781fc3ad213deb16fdcb4b002a97fR83
Merge pull request #2116 from andresailer/patch-2

[v6r11] Remove systemConfig again