Try include rspamd.conf.local.override with high priority

conf/common.conf

@@ -10,7 +10,8 @@ lua = "$CONFDIR/lua/rspamd.lua"
 .include "$CONFDIR/modules.conf"
 
 # User local settings
-.try_include "$CONFDIR/rspamd.conf.local"
+.include(try=true) "$CONFDIR/rspamd.conf.local"
+.include(try=true,priority=10) "$CONFDIR/rspamd.conf.local.override"
 
 modules {
 	path = "$PLUGINSDIR/lua/"