fix a m.nodes race condition in pushPullTrigger
fix a m.nodes race condition in pushPullTrigger

42wim/memberlist,hashicorp/memberlist,oldmantaiter/memberlist,jsternberg/memberlist,aybabtme/memberlist,aybabtme/memberlist,atomx/memberlist,atomx/memberlist,oldmantaiter/memberlist,rbg/memberlist,jsternberg/memberlist,42wim/memberlist,hashicorp/memberlist,rbg/memberlist