I am using Ubuntu 14.04. sudo apt-get update
always give me this option to configure mysql-apt-config.
When you can't do
apt-get purge mysql-apt-config
because you're trapped: It won't execute because dpkg is interrupted, and "sudo dpkg --configure -a" backs you to the broken "configuring mysql-apt-config" screen...
edit: /var/lib/dpkg/info/mysql-apt-config.postinst
add exit
at the beginning , then get rid of the package :
sudo dpkg --configure mysql-apt-config
sudo apt-get remove mysql-apt-config