dpkg: error processing /var/cache/apt/archives/percona-server-common-5.7_5.7.11-4-1.precise_amd64.deb (--unpack):
trying to overwrite '/usr/share/mysql/estonian/errmsg.sys', which is also in package mysql-common 5.6.30-1ubuntu12.04
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Try uninstalling mysql-common first and then reinstall version 5.7.