Fix ExtraParticlesInAcceptance for AllFromSameB = True

Propagate merge of branch 'FixExtraParticlesInAcceptanceGenCut_bsiddi' into 'master'

See original merge request !792 (merged) into 'Sim09'

(cherry picked from commit 514b496f)

b562ec0f Added if ( Bparent == nullptr && m_AllFromSameB ) return false ; in lines 168-177 b60dc594 Remove extra character to fix compilation error