openldap: correct directory hint

Changed files
+1 -1
nixos
modules
services
databases
+1 -1
nixos/modules/services/databases/openldap.nix
···
rootdn cn=admin,dc=example,dc=org
# NOTE: change after first start
rootpw secret
-
directory /var/run/slapd
+
directory /var/db/openldap
''';
'';
};