USN-4593-2: FreeType vulnerability

USN-4593-1 fixed a vulnerability in FreeType. This update provides the corresponding update for Ubuntu 14.04 ESM. Original advisory details: Sergei Glazunov discovered that FreeType did not correctly handle certain malformed font files. If a user were tricked into using a specially crafted font file, a remote attacker could cause FreeType to crash or possibly execute arbitrary code with user privileges.