Do not try to install disks.so file not built on Hurd

debian/changelog

 mariadb-10.3 (1:10.3.11-4) UNRELEASED; urgency=low
 
-  * Open new entry
+  [ Samuel Thibault ]
+  * Do not try to install disks.so file not built on Hurd.
 
  -- Otto Kekäläinen <otto@debian.org>  Tue, 01 Jan 2019 10:23:19 +0200
 

debian/mariadb-server-10.3.install

@@ -44,7 +44,7 @@ usr/bin/wsrep_sst_rsync
 usr/bin/wsrep_sst_rsync_wan
 usr/lib/*/mariadb19/plugin/auth_ed25519.so
 usr/lib/*/mariadb19/plugin/auth_pam.so
-usr/lib/*/mariadb19/plugin/disks.so
+[!hurd-any] usr/lib/*/mariadb19/plugin/disks.so
 usr/lib/*/mariadb19/plugin/file_key_management.so
 usr/lib/*/mariadb19/plugin/ha_archive.so
 usr/lib/*/mariadb19/plugin/ha_blackhole.so