fix brace-mismatch in playbook

[gasuketsu]

Signed-off-by: tharada harada.tomoyuki03@gmail.com

Brace-mismatch found in playbooks/service/librenms.yml, and this causes failure when configuring librenms service like below.

TASK [debops.logrotate : Divert the custom log rotation config] **********************************************************************************************
fatal: [nms.example.com]: FAILED! => {"failed": true, "msg": "[u'{{ php__logrotate__dependent_config }}', u'{{ librenms__logrotate__dependent_config }]']: template error while templating string: unexpected '}'. String: {{ librenms__logrotate__dependent_config }]"}

This commit just fixes the mismatch.