wmaker: fix focused window list order

This patch is fixing the focused next window list order.
As now, the switching was only working for 2 windows.
For example, taking 3 windows called A,B,C.
If the windows list is A,B,C where A is the current focused window.
Focusing on B will result on switching position A and B, thus C will
never be the next window.
For this example the patch is updating the linked list as B,C,A.