ossec-hids/etc/ossec-agent.conf contains double hyphen in comment

[mwmahlberg]

This is illegal as per https://www.w3.org/TR/REC-xml/#sec-comments

[...]the string " -- " (double-hyphen) must not occur within comments.

The occurrence of a double hyphen may prevent proper processing of the file by various XML libraries, not the least of them Python's lxml module, which is used by Ansible.

[ddpbsd]

PR merged, thanks!