auto remove previous leftover socket

weed/command/filer.go

@@ -269,10 +269,10 @@ func (fo *FilerOptions) startFiler() {
 	if runtime.GOOS != "windows" {
 		if *fo.localSocket == "" {
 			*fo.localSocket = fmt.Sprintf("/tmp/seaweefs-filer-%d.sock", *fo.port)
+		}
 		if err := os.Remove(*fo.localSocket); err != nil && !os.IsNotExist(err) {
 			glog.Fatalf("Failed to remove %s, error: %s", *fo.localSocket, err.Error())
 		}
-		}
 		go func() {
 			// start on local unix socket
 			filerSocketListener, err := net.Listen("unix", *fo.localSocket)