Rename "unofficial twisted software foundation" mailing list

[rodrigc]

Glyph wrote this:

Just for everyone's information, the real name for the relevant 
group here is the "Twisted Project Leadership Committee for the
Software Freedom Conservancy".  The reason that the relevant mailing
list is titled "unofficial twisted software foundation" is that we
started off investigating if we could start our own foundation, and
later, when we opted to have the Software Freedom Conservancy as
our fiscal sponsor instead, the name "twisted software foundation"
became "unofficial" because there is no such legal entity.

Please change the name of the mailing list from unofficial twisted software foundation
to Twisted Project Leadership Committee for the Software Freedom Conservancy.

[rodrigc]

@hawkowl @adiroiban can one of you do this?