Security update for qemu (important)

This update for qemu fixes the following issues:

This security issue was fixed:

• CVE-2018-3639: Spectre v4 vulnerability mitigation support for KVM
  guests (bsc#1092885).

  Systems with microprocessors utilizing speculative execution and
  speculative execution of memory reads before the addresses of all prior
  memory writes are known may allow unauthorized disclosure of information
  to an attacker with local user access via a side-channel analysis.

  This patch permits the new x86 cpu feature flag named "ssbd" to be
  presented to the guest, given that the host has this feature, and KVM
  exposes it to the guest as well.

  For this feature to be enabled please use the qemu commandline
  -cpu $MODEL,+spec-ctrl,+ssbd so the guest OS can take advantage of the
  feature.

  spec-ctrl and ssbd support is also required in the host.

This non-security issue was fixed:

• Fix qemu-guest-agent uninstall (boo#1093169)