Update to BIND 9.6.3, the latest from ISC on the 9.6 branch.

Update to BIND 9.6.3, the latest from ISC on the 9.6 branch.

All 9.6 users with DNSSEC validation enabled should upgrade to this
version, or the latest version in the 9.7 branch, prior to 2011-03-31
in order to avoid validation failures for names in .COM as described
here:

https://www.isc.org/announcement/bind-9-dnssec-validation-fails-new-ds-record

In addition the fixes for this and other bugs, there are also the
following:

  * Various fixes to kerberos support, including GSS-TSIG
  * Various fixes to avoid leaking memory, and to problems that could
    prevent a clean shutdown of named