Use isQuark method for correct quark matching.

Fixes LHCBPS-1718.

Phys/DaVinciMCTools/src/BackgroundCategory.cpp

@@ -585,8 +585,7 @@ BackgroundCategory::get_top_mother_of_MCParticle(const LHCb::MCParticle* candida
     finalmother = tmpmother;
     tmpmother = finalmother->mother();
     if (m_ignoreQuarks && tmpmother != NULL) {
-      if ( 1 <= tmpmother->particleID().pid() &&
-           tmpmother->particleID().pid() <= 8 ) {
+        if (tmpmother->particleID().isQuark()) {
             return finalmother;
         }
     }