Reset keyboard focus when a surface is destroyed
Reset keyboard focus when a surface is destroyed

Only pointer focus was reset, resulting in undefined behavior when
acessing keyboardFocus() after all surfaces had gone away.

Change-Id: I8c9f71e2eadbf69de1dc7856f4a05dd309ab95eb
Reviewed-by: Jørgen Lind <6105bb7d7ebdd613cef5835c4a38d29949bd95ac@nokia.com>

ntanibata/qtwayland,locusf/qtwayland-1,Tofee/qtwayland,ntanibata/qtwayland,locusf/qtwayland-1,ntanibata/qtwayland,Tofee/qtwayland,locusf/qtwayland-1,locusf/qtwayland-1,Tofee/qtwayland