Security update for clamav (important)

This update for clamav fixes the following issues:

Security issues fixed:

• CVE-2012-6706: VMSF_DELTA filter inside the unrar implementation allows
  an arbitrary memory write (bsc#1045315).
• CVE-2017-6419: A heap-based buffer overflow that can lead to a denial of
  service in libmspack via a crafted CHM file (bsc#1052449).
• CVE-2017-11423: A stack-based buffer over-read that can lead to a denial
  of service in mspack via a crafted CAB file (bsc#1049423).
• CVE-2018-1000085: An out-of-bounds heap read vulnerability was found in
  XAR parser that can lead to a denial of service (bsc#1082858).
• CVE-2018-0202: Fixed two vulnerabilities in the PDF parsing code
  (bsc#1083915).