avoid nil

fix https://github.com/seaweedfs/seaweedfs/issues/5153

introduced from #5109

weed/command/filer.go

@@ -100,6 +100,7 @@ func init() {
 	filerS3Options.portHttps = cmdFiler.Flag.Int("s3.port.https", 0, "s3 server https listen port")
 	filerS3Options.portGrpc = cmdFiler.Flag.Int("s3.port.grpc", 0, "s3 server grpc listen port")
 	filerS3Options.domainName = cmdFiler.Flag.String("s3.domainName", "", "suffix of the host name in comma separated list, {bucket}.{domainName}")
+	filerS3Options.allowedOrigins = cmdFiler.Flag.String("s3.allowedOrigins", "*", "comma separated list of allowed origins")
 	filerS3Options.dataCenter = cmdFiler.Flag.String("s3.dataCenter", "", "prefer to read and write to volumes in this data center")
 	filerS3Options.tlsPrivateKey = cmdFiler.Flag.String("s3.key.file", "", "path to the TLS private key file")
 	filerS3Options.tlsCertificate = cmdFiler.Flag.String("s3.cert.file", "", "path to the TLS certificate file")