Update OSSEC to v3.0

[emkll]

Description

OSSEC 3.0 was released on July 17th 2018[0], containing a large amount of bug fixes (including 2 security fixes) as well as new major functionality. Of note, it supports whitelisting syscheck md5 hashes in a sqlite database, potentially reducing notification noise.

User Research Evidence

Users like up-to-date packages

User Stories

As a SecureDrop administrator, I would like to have all packages updated and would like to minimize alerts/noise.

[0] https://github.com/ossec/ossec-hids/releases

[emkll]

Initial tests done in #3724 suggest that the 3.0.0 upgrade breaks the registration logic, despite a seemingly successful install. On mon:

root@sd-mon:/var/ossec/bin# ./list_agents -a                                                        │···········································································································································································
** No agent available.