Comment 2 for bug 1336005

Confirmed, this bug prevents users from replacing mysql with percona packages. A quick fix is to extract akonadi -backend-mysql page, modify control file (change Depends), repack .deb file and reinstall (the solution below is more or less working - I'm tweaking the Depends section now)

apt-get install --reinstall --download-only akonadi-backend-mysql
mv /var/cache/apt/archives/akonadi-backend-mysql_1.12.1-0ubuntu1.1_all.deb .
ar x akonadi-backend-mysql_1.12.1-0ubuntu1.1_all.deb
tar xvzf control.tar.gz
vi control
Depends: virtual-mysql-server-core | mariadb-server-core-5.5 | percona-server-server, mysql-client-core-5.5 | mariadb-client-core-5.5 | percona-server-client-5.6, libqt4-sql-mysql
rm control.tar.gz
tar c postinst postrm md5sums control conffiles | gzip -c > control.tar.gz
ar rcs akonadi-backend-mysql_1.12.1-0ubuntu1.1_percona_all.deb debian-binary control.tar.gz data.tar.xz
dpkg -i akonadi-backend-mysql_1.12.1-0ubuntu1.1_percona_all.deb

apt-get install percona-server-server-5.6 percona-server-client-5.6