use auth test files

test/start.sh

@@ -3,7 +3,7 @@
 docker run --rm -it \
 	-u root:root \
 	-v $(pwd)/minetest.conf:/etc/minetest/minetest.conf \
-	-v $(pwd)/players.sqlite:/root/.minetest/worlds/world/players.sqlite \
+	-v $(pwd)/auth.sqlite:/root/.minetest/worlds/world/auth.sqlite \
 	-v $(pwd)/../:/root/.minetest/worlds/world/worldmods/mail_mod \
 	-v mail_world:/root/.minetest/worlds/world/ \
 	--network host \