If, in a single-selection listctrl, a focused item is selected, and the

If, in a single-selection listctrl, a focused item is selected, and the
focus is moved programmatically (SetItemState) without selecting the new
item, the old focused item wasn't deselected, making the listctrl end up
with TWO selected items when the focused item gets selected by the user.
So I made SetItemState deselect the old focused item when the focus is
moved in a single-selection listctrl.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@7776 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775