Bug#840338: libass: CVE-2016-7971: large allocation leading to crash

[Salvatore Bonaccorso]

Control: severity -1 minor

After feedback from MITRE marked it as unimportant, and lowering the
severity. Reasoning in
http://www.openwall.com/lists/oss-security/2016/11/01/10

Regards,
Salvatore