app delegate: fix regression preventing the display of files which were added while the apps is not running

This happens frequently when syncing media via iTunes. Issue introduced in 4bb4d2

Sources/VLCAppDelegate.m

@@ -301,7 +301,7 @@
 - (void)updateMediaList
 {
     NSString *directoryPath = [self directoryPath];
-    NSMutableArray *foundFiles = [NSMutableArray arrayWithObject:@""];
+    NSMutableArray *foundFiles = [NSMutableArray arrayWithArray:[[NSFileManager defaultManager] contentsOfDirectoryAtPath:directoryPath error:nil]];
     NSMutableArray *filePaths = [NSMutableArray array];
     NSURL *fileURL;
     while (foundFiles.count) {