Update querySettings Error Return in Scrape

If there are errors querying namespace mappings, the potential error from querySettings is obscured. Adding an immediate return if there are errors retreiving settings. Signed-off-by: Jonathan Bowe <jonathan@bowedev.com>

Author: Jonathan Bowe

cmd/postgres_exporter/server.go

@@ -119,6 +119,7 @@ func (s *Server) Scrape(ch chan<- prometheus.Metric, disableSettingsMetrics bool
 if !disableSettingsMetrics && s.master {
 if err = querySettings(ch, s); err != nil {
 err = fmt.Errorf("error retrieving settings: %s", err)
+return err
 }
 }