USN-6303-2: ClamAV vulnerability

USN-6303-1 fixed a vulnerability in ClamAV. This update provides
the corresponding update for Ubuntu 14.04 LTS, Ubuntu 16.04 LTS,
and Ubuntu 18.04 LTS.

Original advisory details:

It was discovered that ClamAV incorrectly handled parsing HFS+ files. A
remote attacker could possibly use this issue to cause ClamAV to crash,
resulting in a denial of service.

advisory clamav crash denial of service files issue lts parsing service ubuntu update usn vulnerability