[box-layout] Queue a relayout when removing a child
[box-layout] Queue a relayout when removing a child

Fixes: http://bugzilla.moblin.org/show_bug.cgi?id=9381

pwithnall/mx,pwithnall/mx,jonnylamb/mx,pwithnall/mx,jonnylamb/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx,clutter-project/mx,clutter-project/mx,jonnylamb/mx