add a workaround for https://bugs.launchpad.net/maria/+bug/985828 that causes...

add a workaround for https://bugs.launchpad.net/maria/+bug/985828 that causes wrong result in Resource_zGetInventoryList etc.
(cherry picked from commit f22f2c9d5718ecf0229eb947cbac7ed335427310)

slapos/recipe/generic_mysql/template/my.cnf.in

@@ -8,6 +8,10 @@
 # Loud fail is really required in such case.
 sql-mode="NO_ENGINE_SUBSTITUTION"
 
+# Workaround for https://bugs.launchpad.net/maria/+bug/985828
+# that causes wrong result in Resource_zGetInventoryList etc.
+optimizer_switch = derived_merge=off
+
 skip-show-database
 %(networking)s
 socket = %(socket)s