Disable disks.disks test

This failed on most Launchpad architectures, as the disk information
does not seem to be available on Launchpad builders. A better fix will
be done by upstream later to the actual test code itself.

debian/patches/disable-test-disks.patch

+Author: Vicentiu Ciorbaru <vicentiu@mariadb.org>
+Date:   Wed Jul 4 13:29:55 2018 +0300
+
+    Disable disks.disks test
+
+--- /dev/null
++++ b/plugin/disks/mysql-test/disks/disabled.def
+@@ -0,0 +1 @@
++disks                    : does not work on Launchpad

debian/patches/series

@@ -3,6 +3,7 @@ scripts__mysql_create_system_tables__no_test.patch
 scripts__mysqld_safe.sh__signals.patch
 scripts__mysql_install_db.sh__no_test.patch
 mysql-test__db_test.patch
+disable-test-disks.patch
 replace_dash_with_bash_mbug675185.patch
 extend_default_test_timeout_for_tokudb.patch
 remove_rename_mariadb-server_files_in.patch