Univention Corporate Server 4.1 erratum 498 (extended maintenance)

This update of the Linux kernel to version 4.9.78 addresses the following
issues:
* Systems with microprocessors utilizing speculative execution and indirect
  branch prediction may allow unauthorized disclosure of information to an
  attacker with local user access via a side-channel analysis (CVE-2017-5715)
* kvm: stack-based out-of-bounds read via vmcall instruction (CVE-2017-17741)
* Stack information leak in the EFS element (CVE-2017-1000410)

This is a major update for the Linux kernel as Linux kernel version 4.1 is no
longer maintained and does no longer get any security updates! Backporting
the patches for 'Meltdown' and 'Spectre' is considered too risky.
The Linux kernel provides a stable ABI so user programs should not notice the
upgrade in general. Low-level programs like 'udev' have been updated to
support both old and new Linux kernels, see also Errata 490-494.
On the other hand kernel internal details have changed, which might break
external kernel modules.