debian warns of insecure root password when a plugin is used

SELECT count(*) FROM mysql.user WHERE user='root' and password=''

can report insecure root passwords even if a plugin is used.

If a bit unfair to report an unused password field as insecure if a plugin is set.

https://github.com/grooverdan/mariadb-server/tree/5.5-debian-insecure-root-plugin-empty is a patch that corrects this by testing adding and plugin='' in the sql. I submit this under the MCA.

FYI Otto Kekäläinen, Ondřej Surý