Bug#848289: ruby-riddle: (build-)depends on mysql-{client,server}

[李健秋]

Package: ruby-riddle
Followup-For: Bug #848289

Got confirm from IRC that the MariaDB fail tests cannot be reproduced
on one of our porterbox:
  18:03 < zumbi> AndrewLee: I tried to reproduce, but git built fine in
  a porterbox

I'd roll a new upload from git shortly.

Best regards,
-Andrew