cmd/syncthing: Handle -logfile again (fixes #3931)

The monitor process should not set STNORESTART as this indicates the
intention from the user. Setting STMONITORED is enough, as this tells
the next Syncthing instance that it is running under the monitor
process.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3932

cmd/syncthing/main.go

@@ -401,7 +401,7 @@ func main() {
 		return
 	}
 
-	if options.noRestart {
+	if innerProcess || options.noRestart {
 		syncthingMain(options)
 	} else {
 		monitorMain(options)

cmd/syncthing/monitor.go

@@ -35,7 +35,6 @@ const (
 )
 
 func monitorMain(runtimeOptions RuntimeOptions) {
-	os.Setenv("STNORESTART", "yes")
 	os.Setenv("STMONITORED", "yes")
 	l.SetPrefix("[monitor] ")