xorg-server - security update

Ilja van Sprundel of IOActive discovered several security issues in the
X.org X server, which may lead to privilege escalation or denial of
service.

For the stable distribution (wheezy), these problems have been fixed in
version 1.12.4-6+deb7u5.

For the upcoming stable distribution (jessie), these problems will be
fixed soon.

For the unstable distribution (sid), these problems have been fixed in
version 2:1.16.2.901-1.

We recommend that you upgrade your xorg-server packages.