Security update for Xen (important)

Xen was updated to fix two security issues:

   * CVE-2015-3209: Heap overflow in qemu pcnet controller allowing guest
     to host escape. (XSA-135, bsc#932770)
   * CVE-2015-4164: DoS through iret hypercall handler. (XSA-136,
     bsc#932996)

Security Issues:

   * CVE-2015-4164
     &lt;<a href="http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4164">http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4164</a>&gt;
   * CVE-2015-3209
     &lt;<a href="http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3209">http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3209</a>&gt;