No version metrics when default metrics disabled

Author: samsk

cmd/postgres_exporter/postgres_exporter.go

@@ -1231,8 +1231,10 @@ func (e *Exporter) checkMapVersions(ch chan<- prometheus.Metric, server *Server)
 	versionDesc := prometheus.NewDesc(fmt.Sprintf("%s_%s", namespace, staticLabelName),
 		"Version string as reported by postgres", []string{"version", "short_version"}, server.labels)
 
-	ch <- prometheus.MustNewConstMetric(versionDesc,
-		prometheus.UntypedValue, 1, versionString, semanticVersion.String())
+	if !e.disableDefaultMetrics {
+		ch <- prometheus.MustNewConstMetric(versionDesc,
+			prometheus.UntypedValue, 1, versionString, semanticVersion.String())
+	}
 	return nil
 }