use proper error code for unsupported anonymous s3 access

src/api/signature.rs

@@ -165,9 +165,9 @@ fn parse_authorization(
 }
 
 fn parse_query_authorization(headers: &HashMap<String, String>) -> Result<Authorization, Error> {
-	let algo = headers
-		.get("x-amz-algorithm")
-		.ok_or_bad_request("X-Amz-Algorithm not found in query parameters")?;
+	let algo = headers.get("x-amz-algorithm").ok_or_else(|| {
+		Error::Forbidden("Garage does not support anonymous users yet".to_owned())
+	})?;
 	if algo != "AWS4-HMAC-SHA256" {
 		return Err(Error::BadRequest(
 			"Unsupported authorization method".to_string(),