Fix of paths for g4.11 installation

This MR fixes PATH, LD_LIBRARY_PATH and ROOT_INCLUDE_DIR that was generated for LHCb build of Geant4.11. The Geant4 installation tree has changed since version G4.10 and therefore all the LHCb-generated paths were wrong. This resulted in particular in GiGaMT not being able to load and therefore all the Gauss/Gaussino tests failing in the nightlies.