bug: nil check against the series set not errors

Signed-off-by: gotjosh <josue.abreu@gmail.com>

rules/alerting.go

@@ -281,8 +281,8 @@ func (r *AlertingRule) QueryforStateSeries(ctx context.Context, q storage.Querie
 		}
 		matchers = append(matchers, mt)
 	})
-	sset := q.Select(ctx, false, nil, matchers...)
 
+	sset := q.Select(ctx, false, nil, matchers...)
 	return sset, sset.Err()
 }
 

rules/group.go

@@ -676,7 +676,7 @@ func (g *Group) RestoreForState(ts time.Time) {
 		}
 
 		// No results for this alert rule.
-		if err == nil {
+		if sset == nil {
 			level.Debug(g.logger).Log("msg", "Failed to find a series to restore the 'for' state", labels.AlertName, alertRule.Name())
 			continue
 		}