gnutls: fix CVE-2014-3466

Jira: SB-3003
Integrate  communuity fix for the issue CVE-2014-3466
Signed-off-by: Priyanka Shobhan <priyanka_shobhan@mentor.com>
Merge pull request #223 from pshobhan/pshobhan/bugfix/CVE-2014-3466

gnutls: fix CVE-2014-3466