Fix conkbg() in ckotio.c for OpenWatcom on OS/2

[davidrg]

The body of conkbg() towards the end of ckotio.c is #ifdefd out when targeting OS/2 with OpenWatcom as the code doesn't compile. It seems like there is something wrong with the OpenWatcom OS/2 headers but I can't really be sure. Might need access to the IBM Compilers headers to figure this one out.

The function itself is only used to populate the \v(keyboard) variable - Kermit 95 itself doesn't use the value for anything at all, so its absence isn't likely to break anything besides any user scripts that want to know the keyboard model for some reason.