Do not fatal on happy exit

Summary: When we exit normally, through expected signal handling, we should not be returning a non-zero status code. Move the logging to `Info` and place it ahead of the actual shutdown invocation.

Reviewed By: leoleovich

Differential Revision: D57128031

fbshipit-source-id: 7900c47ad21bca3e1ea50ba20cb53072e14ab0fb

dnsrocks/cmd/dnsrocks/dnsrocks.go

@@ -277,12 +277,13 @@ Currently two types of trigger files are supported:
 
 	go srv.LogMapAge()
 	go srv.DumpBackendStats()
+
 	sig := make(chan os.Signal, 1)
 	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
 	s := <-sig
-	srv.Shutdown()
+	glog.Infof("Signal (%v) received, stopping\n", s)
 
-	glog.Fatalf("Signal (%v) received, stopping\n", s)
+	srv.Shutdown()
 }
 
 func failOnErr(err error, msg string) {