Remove more dead code

Signed-off-by: Joe Adams <github@joeadams.io>

Author: sysadmind

cmd/postgres_exporter/probe.go

@@ -85,8 +85,6 @@ func handleProbe(logger log.Logger, excludeDatabases []string) http.HandlerFunc
 // Run the probe
 pc, err := collector.NewProbeCollector(tl, excludeDatabases, registry, dsn)
 if err != nil {
-// probeSuccessGauge.Set(0)
-// probeDurationGauge.Set(time.Since(start).Seconds())
 http.Error(w, err.Error(), http.StatusInternalServerError)
 return
 }