Preconfiguring packages ...
(Reading database ... 341780 files and directories currently installed.)
Preparing to unpack .../mysql-server-core-5.6_5.6.19-0ubuntu0.14.04.1_amd64.deb ...
Unpacking mysql-server-core-5.6 (5.6.19-0ubuntu0.14.04.1) ...
dpkg: error processing archive /var/cache/apt/archives/mysql-server-core-5.6_5.6.19-0ubuntu0.14.04.1_amd64.deb (--unpack):
 trying to overwrite '/usr/share/mysql/charsets/geostd8.xml', which is also in package mysql-common 5.6.21-1ubuntu14.04
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Preparing to unpack .../mysql-server-5.6_5.6.19-0ubuntu0.14.04.1_amd64.deb ...
Unpacking mysql-server-5.6 (5.6.19-0ubuntu0.14.04.1) ...
dpkg: error processing archive /var/cache/apt/archives/mysql-server-5.6_5.6.19-0ubuntu0.14.04.1_amd64.deb (--unpack):
 trying to overwrite '/usr/share/mysql/errmsg-utf8.txt', which is also in package mysql-common 5.6.21-1ubuntu14.04
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
E: Sub-process /usr/bin/dpkg returned an error code (1)