s3: fix configuring IAM for the same user

hi, how can I add bucket permission to a user now?
Previously, if I needed to add permission to an existing credential, I simply repeated the s3.configure command with a different bucket name.
Now I am getting error:
duplicate accessKey[ХХХХ], already configured in user[YYYY]

s3.configure -access_key key -actions Read,Write,List -buckets bucket1 -secret_key secr -user user1
s3.configure -access_key key -actions Read,Write,List -buckets bucket2 -secret_key secr -user user1

weed/filer/s3iam_conf.go

@@ -43,7 +43,7 @@ func CheckDuplicateAccessKey(s3cfg *iam_pb.S3ApiConfiguration) error {
 		for _, cred := range ident.Credentials {
 			if userName, found := accessKeySet[cred.AccessKey]; !found {
 				accessKeySet[cred.AccessKey] = ident.Name
-			} else {
+			} else if userName != ident.Name {
 				return fmt.Errorf("duplicate accessKey[%s], already configured in user[%s]", cred.AccessKey, userName)
 			}
 		}