[SECURITY] [DLA 370-1] bind9 security update

Package : bind9
Version : 1:9.7.3.dfsg-1~squeeze18
CVE ID : CVE-2015-8000

It was discovered that the BIND DNS server does not properly handle the
parsing of incoming responses, allowing some records with an incorrect
class to be accepted by BIND instead of being rejected as malformed.
This can trigger a REQUIRE assertion failure when those records are
subsequently cached. A remote attacker can exploit this flaw to cause a
denial of service against servers performing recursive queries.