Security update for xen (important)

xen was updated to fix two security issues.

These security issues were fixed:

• CVE-2015-3259: xl command line config handling stack overflow
  (bsc#935634, XSA-137).
• CVE-2015-5154: Host code execution via IDE subsystem CD-ROM (bsc#938344).

These non-security issues were fixed:

• Restart of xencommons service did lead to loss of xenstore data
  (bsc#935256).
• Kdump did not work in a XEN environment (bsc#925466).