desktop-shell: Avoid spurious configure events for xdg-shell activation
This is a minor re-work of how we de-activate and activate the surfaces in desktop-shell. As activate() is being used for handling keyboard input events, this basically rectifies that such that activation happens only if the passed surface is different from the currently focused one.
Fixes: #593 (closed)
Signed-off-by: Marius Vlad marius.vlad@collabora.com