rafthttp: add snapshot limit const (#11846)
rafthttp: add snapshot limit const (#11846)


cockroachdb/etcd,dannysauer/etcd,ajityagaty/etcd,mqliang/etcd,ajityagaty/etcd,mkumatag/etcd,mqliang/etcd,dannysauer/etcd,mkumatag/etcd,gyuho/etcd,ajityagaty/etcd,rnaveiras/etcd,etcd-io/etcd,coreos/etcd,mqliang/etcd,mkumatag/etcd,li-ang/etcd,li-ang/etcd,etcd-io/etcd,cockroachdb/etcd,coreos/etcd,gyuho/etcd,rnaveiras/etcd,etcd-io/etcd,rnaveiras/etcd