macosx: Remove unused variable

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/macosx/VLCVoutWindowController.m

@@ -275,7 +275,6 @@ void WindowClose(vout_window_t *p_wnd)
         if (!b_video_deco)
             mask |= NSResizableWindowMask;
 
-        BOOL b_no_video_deco_only = !b_video_wallpaper;
         o_new_video_window = [[VLCVideoWindowCommon alloc] initWithContentRect:window_rect styleMask:mask backing:NSBackingStoreBuffered defer:YES];
         [o_new_video_window setDelegate:o_new_video_window];
         [o_new_video_window setReleasedWhenClosed: NO];