Please backport pyspf 2.0.12t-1 (universe) from xenial

Please backport pyspf 2.0.12t-1 (universe) from xenial to trusty.

Reason for the backport:
========================
Works better with some newer versions of bind

Testing:
========
Mark off items in the checklist [X] as you test them, but please leave the checklist so that backporters can quickly evaluate the state of testing.

You can test-build the backport in your PPA with backportpackage:
$ backportpackage -u ppa:<lp username>/<ppa name> -s xenial -d trusty pyspf

* trusty:
[ X ] Package builds without modification
[ X ] python-spf installs cleanly and runs
[ X ] python3-spf installs cleanly and runs
[ X ] spf-tools-python installs cleanly and runs

Reverse dependencies:
=====================
The following reverse-dependencies need to be tested against the new version of pyspf. For reverse-build-dependencies (-Indep), please test that the package still builds against the new pyspf. For reverse-dependencies, please test that the version of the package currently in the release still works with the new pyspf installed. Reverse- Recommends, Suggests, and Enhances don't need to be tested, and are listed for completeness-sake.

python-spf
----------
* spf-milter-python
  [ X ] trusty (Reverse-Depends)
* tumgreyspf
  [ X ] trusty (Reverse-Depends)
* bley
  [ X ] trusty (Reverse-Depends)

python3-spf
-----------
* postfix-policyd-spf-python
  [ X ] trusty (Reverse-Depends)

spf-tools-python
----------------