datetime/timestamps/4.1.12

[DePhillips, Michael P]

Hello,
 
I just upgraded to 4.1.12 from 4.0.22 and my timestamps changed formats to 
%Y-%m-%d %H:%i:%s
 
So I added the following lime to my my.cnf file
 
datetime_format=%Y%m%d%H%i%s
 
Which is the format I prefer, I  restart the server and my time stamps still 
appear as 
%Y-%m-%d %H:%i:%s
 
The 'show variables' command now confirms that the format is what I defined in 
the my.cnf but the output of the query does not change...
 
What am I missing?
 
Thanks,
Michael