Upgrade to BIND version 9.6-ESV-R7, the latest from ISC.

Upgrade to BIND version 9.6-ESV-R7, the latest from ISC.

Feature Change

*  BIND now recognizes the TLSA resource record type, created to
   support IETF DANE (DNS-based Authentication of Named Entities)

Bug Fix

*  The locking strategy around the handling of iterative queries
   has been tuned to reduce unnecessary contention in a multi-
   threaded environment.

Other critical bug fixes are included.

All BIND users are encouraged to upgrade.

git-svn-id: svn://svn.freebsd.org/base/stable/8@236197 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f