gtk: fix scrollbar drawing with Clearlooks
gtk: fix scrollbar drawing with Clearlooks

Change-Id: Ia1afbfd027bf473f23b83239562f542d0157d549

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