don't crash on layout of ooo55381-1.sxw
don't crash on layout of ooo55381-1.sxw

The pLay here is getting joined and thus deleted in a stack of
FormatLayoutTabs so set it as unjoinable for the duration that
we expect pLay to remain valid

Change-Id: Iedfaf710022ad19c0f415cee84f70c74dd7dbd96

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core