gridfixes: impl_getColumnForOrdinate:no need to subs m_nRowHeaderWidthPixel
gridfixes: impl_getColumnForOrdinate:no need to subs m_nRowHeaderWidthPixel

m_aColumnWidths already contains it

Change-Id: I404c58fb0b32db7b7b7bf60be997f81709908ceb
Reviewed-on: https://gerrit.libreoffice.org/556
Reviewed-by: Miklos Vajna <16f13092e03e3d9e997de904d0f86cc803fb6ef7@suse.cz>
Tested-by: Miklos Vajna <16f13092e03e3d9e997de904d0f86cc803fb6ef7@suse.cz>

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