Revision 1226945

kmix: Avoid the use of QString.sprintf().

This is generally discouraged and also doesn't deal gracefully with UTF8
encoded data (due to explicityly calling toAscii()) so use the
more modern QString().arg(..) construct and leave the data encoding
as is. This may result in writing some UTF8 data into the config files
but this should be handled gracefully.

CCBUG: 265317
CCBUG: 237239
CCBUG: 264835