Security update for qemu (moderate)

This update for qemu fixes the following issues:

These security issues were fixed:

• CVE-2018-12617: qmp_guest_file_read had an integer overflow that could
  have been exploited by sending a crafted QMP command (including
  guest-file-read with a large count value) to the agent via the listening
  socket causing DoS (bsc#1098735).
• CVE-2018-11806: Prevent heap-based buffer overflow via incoming
  fragmented datagrams (bsc#1096223).

With this release the mitigations for Spectre v4 are moved the the patches
from upstream (CVE-2018-3639, bsc#1092885).

This feature was added:

• Add support for block resize support for disks through the monitor
  (bsc#1094725).

This update was imported from the SUSE:SLE-12-SP3:Update update project.