Fix bug add favorite entry

See https://github.com/marienfressinaud/FreshRSS/issues/494

app/Controllers/importExportController.php

@@ -284,7 +284,7 @@ class FreshRSS_importExport_Controller extends Minz_ActionController {
 		$url = $origin[$key];
 		$name = $origin['title'];
 		$website = $origin['htmlUrl'];
-		$error = false;
+
 		try {
 			// Create a Feed object and add it in DB
 			$feed = new FreshRSS_Feed($url);

app/Models/EntryDAO.php

@@ -65,7 +65,7 @@ class FreshRSS_EntryDAO extends Minz_ModelPdo {
 		}
 
 		if (!isset($existingGuids[$entry->guid()]) &&
-				($feedHistory != 0 || $eDate  >= $date_min)) {
+				($feedHistory != 0 || $eDate >= $date_min || $entry->isFavorite())) {
 			$values = $entry->toArray();
 
 			$useDeclaredDate = empty($existingGuids);