fdo#59249: mailmerge.py: some more bytes vs. str mangling
fdo#59249: mailmerge.py: some more bytes vs. str mangling

Obvious problems are in debug code only.

Change-Id: I45aafb4f194a5a020bb95bd96c2d92ca7ee578f8

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