Show submenu from menu list on hardware MENU key press

Submenu is not shown when menu list is open by pressing
hardware MENU key. But it is shown properly when menu is
open from overflow button.
This change will unify the behavior of MENU key &
overflow button.

Crs-Fixed: 622050
Change-Id: I91e336df845febf048583989c8c6b831e04856b1