[SRU trusty, trusty/lts-backport-utopic, vivid] CVE-2015-7312 -- Use-after-free in Linux kernel with aufs mmap patch

[Andy Whitcroft]

We have been applying the aufs-mmap.patch to our trees since trusty, we
did not do so before so precise is not affected.  Following this email
are patches for trusty, trusty/lts-backport-utopic, and vivid.  This fix
is already applied to wily.

Proposing for SRU to trusty, trusty/lts-backport-utopic, and vivid.

-apw