Security update for libxml2 (important)

This update for libxml2 fixes the following security issues:

• CVE-2016-2073, CVE-2015-8806, CVE-2016-1839: A Heap-buffer overread was
  fixed in libxml2/dict.c [bsc#963963, bsc#965283, bsc#981114].
• CVE-2016-4483: Code was added to avoid an out of bound access when
  serializing malformed strings [bsc#978395].
• CVE-2016-1762: Fixed a heap-based buffer overread in xmlNextChar
  [bsc#981040].
• CVE-2016-1834: Fixed a heap-buffer-overflow in xmlStrncat [bsc#981041].
• CVE-2016-1833: Fixed a heap-based buffer overread in htmlCurrentChar
  [bsc#981108].
• CVE-2016-1835: Fixed a heap use-after-free in xmlSAX2AttributeNs
  [bsc#981109].
• CVE-2016-1837: Fixed a heap use-after-free in htmlParsePubidLiteral and
  htmlParseSystemiteral [bsc#981111].
• CVE-2016-1838: Fixed a heap-based buffer overread in
  xmlParserPrintFileContextInternal [bsc#981112].
• CVE-2016-1840: Fixed a heap-buffer-overflow in xmlFAParsePosCharGroup
  [bsc#981115].
• CVE-2016-4447: Fixed a heap-based buffer-underreads due to xmlParseName
  [bsc#981548].
• CVE-2016-4448: Fixed some format string warnings with possible format
  string vulnerability [bsc#981549],
• CVE-2016-4449: Fixed inappropriate fetch of entities content
  [bsc#981550].
• CVE-2016-3705: Fixed missing increment of recursion counter.

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