skins2: replace all stat() with vlc_stat()
skins2: replace all stat() with vlc_stat()

(cherry picked from commit 49c72956b06beceda573b3f6eb5d57a3b5ddb414)
Signed-off-by: Erwan Tulou <e27b355b6a481153648f03262de342e9eb9e2807@videolan.org>

jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2