[SAC] SPF record for osgeo.org

[Sandro Santilli]

FYI: I've added a:tracsvn.osgeo.osuosl.org
to the SPF record for lists.osgeo.org, to
allow notification mails sent from Gogs to
not be considered spam.

The current full SPF is then:

  v=spf1 mx a:mail.osgeo.org \
            a:lists.osgeo.org \
            a:mail.osgeo.osuosl.org \
            a:tracsvn.osgeo.osuosl.org \
            -all

--strk;