[spec] Fix require package.

- Remove "mysql-server" package
  - Because there is some possibility of doing that user put MySQL (or
    MariaDB) server on other machine.
- Add "MySQL-python" package
  - Because ```hatohol-db-initiator``` uses it.

This Pull Request is related to #768.
If you want to fix spec file, please, let me know, commit your change into this branch.