Security update for libvirt (important)

This update for libvirt fixes the following issues:

Security issues fixed:

• CVE-2017-5715: Fixes for speculative side channel attacks aka
  "SpectreAttack" (var2) (bsc#1079869).
• CVE-2018-6764: Fixed guest executable code injection via libnss_dns.so
  loaded by libvirt_lxc before init (bsc#1080042).
• CVE-2018-1064: Fixed denial of service when reading from guest agent
  (bsc#1083625).

Non-security issues fixed:

• Error starting domain: internal error: No usable sysfs TPM cancel file
  could be found (bsc#1078808).
• SUSE Linux Enterprise 11 SP4 hvm converted to pvhvm. Unless vm memory is
  on gig boundary, vm won’t boot (bsc#1082041).