Answer a panicking verb with an error, say flag errors in the answer, and leave refused logins out of D15

Read verbs now run in the serving process, where a panic would end every
call; refused logins are nobody's reconnect loop (review of hq issue 327).

cmd/mesh-controller/reconnects.go

@@ -64,7 +64,12 @@ func probeReconnects(ctx context.Context, d *doctor) ([]conditions.Observation,
 	if len(on) == 0 {
 		return nil, nil // no bus module assigned: a mesh whose bus is not the mesh's module
 	}
-	read, err := askClosed(ctx, d.js.Conn(), on[0])
+	return reconnectsOn(ctx, d.js.Conn(), on[0])
+}
+
+// reconnectsOn asks the bus module on its machine and says who reconnects in a loop.
+func reconnectsOn(ctx context.Context, conn *nats.Conn, node string) ([]conditions.Observation, error) {
+	read, err := askClosed(ctx, conn, node)
 	if isNothingServes(err) {
 		// A bus module older than its tool has nothing it can say, which is not a failure of the probe.
 		return nil, nil
@@ -100,6 +105,11 @@ func reconnecting(read closedConnections) []conditions.Observation {
 	}
 	var out []conditions.Observation
 	for _, u := range read.Users {
+		if u.User == "" || strings.HasPrefix(u.User, "(") {
+			// Refused before it logged in: no client of the mesh's, so nobody's reconnect loop. A login
+			// refused again and again is a question of its own, not this probe's.
+			continue
+		}
 		perHour := float64(u.Dropped) / hours
 		if perHour <= reconnectBound {
 			continue