~SdUnoPageBackground() gets a SolarMutexGuard
~SdUnoPageBackground() gets a SolarMutexGuard

Change-Id: I76582bb6a1a8dee56611f1463d3e63246eefb310

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