Error during installing MySQL server 5.5 on Ubuntu 14.04

I got following error when try to install mysql-server-5.5 on ubuntu 14.04:

[ERROR] /usr/sbin/mysqld: unknown variable 'log_slow_verbosity=query_plan'

After that I got

start: Job failed to start

To fix that:

open /etc/mysql/my.cnf for edit and comment following string


Then start installation from scratch:

sudo apt-get install mysql-server