What to make of this week’s primary election? On the one hand, a slew of incumbent Democrats had credible challengers — which suggests an era of intra-party stasis and timidity has finally come to a close. Then again…those challengers all lost. So maybe incumbency still has some advantages? In this, the first Scrum of the GBH era, Peter Kadzis and Adam Reilly kick it around with Boston Globe columnist Joan Vennochi — along with Joe Kennedy’s future and whether the drama in #mapoli is done for the year (spoiler: it isn’t).