Bug#858255: Multiple security issues

[Salvatore Bonaccorso]

Control: clone -1 -2
Control: retitle -2 virglrenderer: CVE-2017-6386

Hi

There was an upload to unstable (0.6.0-1). Out of the CVEs one was not
yet fixed: CVE-2017-6386. Cloning to record that one separately.

Regards,
Salvatore