macosx/framework: Add video_dirs to the list of MediaDiscoverer by default.

Sources/VLCMediaDiscoverer.m

@@ -77,6 +77,7 @@ static void HandleMediaDiscovererEnded( const libvlc_event_t * event, void * use
         availableMediaDiscoverer = [[NSArray arrayWithObjects:
                                 [[[VLCMediaDiscoverer alloc] initWithName:@"sap"] autorelease],
                                 [[[VLCMediaDiscoverer alloc] initWithName:@"freebox"] autorelease],
+                                [[[VLCMediaDiscoverer alloc] initWithName:@"video_dir"] autorelease],
                                 [[[VLCMediaDiscoverer alloc] initWithName:@"shoutcast"] autorelease],
                                 [[[VLCMediaDiscoverer alloc] initWithName:@"shoutcasttv"] autorelease], nil] retain];
     }