You fed the installation a bad username/password, and it could not install mythtv-database.
From the log:
Setting up mythtv-database (0.21.0+fixes19961-0ubuntu8) ...
* Starting MySQL database server mysqld
...done.
* Checking for corrupt, not cleanly closed and upgrade needing tables.
Failed to create or modify database (incorrect admin username/password?)
Try:
sudo dpkg-reconfigure mythtv-database
You fed the installation a bad username/password, and it could not install mythtv-database.
From the log:
Setting up mythtv-database (0.21.0+ fixes19961- 0ubuntu8) ...
* Starting MySQL database server mysqld
...done.
* Checking for corrupt, not cleanly closed and upgrade needing tables.
Failed to create or modify database (incorrect admin username/password?)
Try:
sudo dpkg-reconfigure mythtv-database