Fix unreferenced parameter warnings

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Fix compilation warnings of gitdll.c

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Repository Browser: Do not show revert, copy path, copy hash menu items if no item selected

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>