[FeedExpander] widen guid use as uri provider

Signed-off-by: Pierre Mazière <pierre.maziere@gmx.com>

lib/FeedExpander.php

@@ -153,7 +153,10 @@ abstract class FeedExpander extends BridgeAbstract {
 
 		if(isset($feedItem->guid)){
 			foreach($feedItem->guid->attributes() as $attribute=>$value){
-				if($attribute === 'isPermaLink' && $value === "true"){
+				if($attribute === 'isPermaLink' && (
+					$value === 'true' ||
+					filter_var($feedItem->guid,FILTER_VALIDATE_URL)
+				)){
 					$item['uri'] = $feedItem->guid;
 					break;
 				}