/etc/mysql/my.cnf.fallback doesn't existと言われたら(mysql)

apt使ってて

update-alternatives: error: alternative path /etc/mysql/my.cnf.fallback doesn't exist
dpkg: error processing package mysql-common (--configure):
 subprocess installed post-installation script returned error exit status 2
dpkg: dependency problems prevent configuration of mysql-client-5.7:
 mysql-client-5.7 depends on mysql-common (>= 5.5); however:
  Package mysql-common is not configured yet.

と言われたとき、

mv /etc/mysql/my.cnf /etc/mysql/my.cnf.d

touch /etc/mysql/my.cnf.fallback 

それで apt -f install

んで

mv /etc/mysql/my.cnf.d /etc/mysql/my.cnf

すればなおる。これでいいかどうかは謎。