[debian-mysql] Bug#917872: Automatically uninstall/reinstall Mroonga plugin on upgrade

[Otto Kekäläinen]

Control: retitle -1 Ensure Mroonga plugin install/upgrade/uninstall
correctly automatically

Current status:

- mariadb-plugin-mroonga.postinst does the install
- mariadb-plugin-mroonga.prerm does the uninstalls
- both seem to run on upgrades


The current problem is that on upgrades mariadb-plugin-mroonga.prerm
runs at a time when the mysqld is not running, and thus fails. Since
there is no real need to unstall on an upgrade this does not matter,
but looks ugly:

....
Preparing to unpack .../7-mariadb-plugin-mroonga_10.3.14-1_amd64.deb ...
ERROR 2002 (HY000): Can't connect to local MySQL server through socket
'/var/run/mysqld/mysqld.sock' (2 "No such file or directory")
Unpacking mariadb-plugin-mroonga (1:10.3.14-1) over (10.1.37-0+deb9u1) ...
Preparing to unpack
.../8-mariadb-plugin-cracklib-password-check_10.3.14-1_amd64.deb ...
Unpacking mariadb-plugin-cracklib-password-check:amd64 (1:10.3.14-1)
over (10.1.37-0+deb9u1) ...
Preparing to unpack .../9-default-mysql-server_1.0.5_all.deb ...
Unpacking default-mysql-server (1.0.5) over (1.0.2) ...
....