A comment text edit (provided by editeng) works with relative twip
coordinates, conversion of the cursor position to absolute twips happens
in ImpEditView::ShowCursor(), provided that the pOutWin member has a map
mode origin that respresents the offset correctly.

This is not true during SwSidebarWin::DeactivatePostIt(), the map mode
origin is already reset back to 0, so just don't emit callbacks during
shutdown, the sw body text cursor will be shown later anyway.

Change-Id: I02c15bb9fad99db8e43fd2f37df770dd165be788