Log Message:
net/bind911: Update to 9.11.27

- Changelog:
  * Bug Fixes:
    - Multiple threads could attempt to destroy a single RBTDB instance at the
      same time, resulting in an unpredictable but low-probability assertion
      failure in free_rbtdb(). This has been fixed. [GL #2317]

- Full changelog at:
https://downloads.isc.org/isc/bind9/9.11.27/RELEASE-NOTES-bind-9.11.27.html