library: show correct 'empty folder' labels on iPhone

(cherry picked from commit ce74b8f005929bc7c6bcf137cad56743d4c98dbd)

Sources/VLCLibraryViewController.m

@@ -305,9 +305,9 @@ static NSString *kUsingTableViewToShowData = @"UsingTableViewToShowData";
                 }
                 _reorderLayout = [[LXReorderableCollectionViewFlowLayout alloc] init];
                 [self.collectionView setCollectionViewLayout:_reorderLayout animated:NO];
-                _libraryMode = VLCLibraryModeFolder;
             }
         }
+        _libraryMode = VLCLibraryModeFolder;
         @synchronized(self) {
             _foundMedia = [NSMutableArray arrayWithArray:[folder sortedFolderItems]];
         }