USN-4656-2: X.Org X Server vulnerabilities

USN-4656-2: X.Org X Server vulnerabilities

USN-4656-1 fixed several vulnerabilities in X.Org. This update provides
the corresponding update for Ubuntu 14.04 ESM.

Original advisory details:

Jan-Niklas Sohn discovered that the X.Org X Server XKB extension
incorrectly handled certain inputs. A local attacker could possibly use
this issue to escalate privileges.
Source: USN-4656-2: X.Org X Server vulnerabilities