ports-mgmt: remove 'Created by' lines

A big Thank You to the original contributors of these ports:

  *  "Waitman Gobble" <uzimac@da3m0n8t3r.com>
  *  Akinori MUSHA aka knu <knu@idaemons.org>
  *  Alex Dupre <ale@FreeBSD.org>
  *  Alex Stangl <alex@stangl.us>
  *  Anders F Bjorklund <afb@users.sourceforge.net>
  *  Benjamin Lutz
  *  Brendan Molloy <brendan+freebsd@bbqsrc.net>
  *  Conrad J. Sabatier <conrads@cox.net>
  *  Edwin Groothuis (edwin@mavetju.org)
  *  Emanuel Haupt <ehaupt@FreeBSD.org>
  *  Gabriel Linder <linder.gabriel@gmail.com>
  *  Heiner <h.eichmann@gmx.de>
  *  Ilya A. Arkhipov <rum1cro@yandex.ru>
  *  John Marino <marino@FreeBSD.org>
  *  Jun-ichiro itojun Hagino <itojun@itojun.org>
  *  Kubilay Kocak <koobs@FreeBSD.org>
  *  Mamoru Sakaue / MwGhennndo
  *  Martin Kammerhofer
  *  Matthew Seaman
  *  Matthew Seaman <m.seaman@infracaninophile.co.uk>
  *  Matthias Andree <mandree@FreeBSD.org>
  *  Matthias Schmidt
  *  Pawel Pekala <pawel@FreeBSD.org>
  *  Philip M. Gollucci <pgollucci@p6m7g8.com>
  *  Philipp Wuensche <cryx-ports@h3q.com>
  *  Richard Gallamore <ultima@FreeBSD.org>
  *  Romain Tartiere <romain@FreeBSD.org>
  *  Romain Tartiere <romain@blogreen.org>
  *  Securedog <securedog@users.sourceforge.jp>
  *  Sergei Kolobov <sergei@kolobov.com>
  *  Shaun Amott <shaun@inerd.com>
  *  Stefan Walter <sw@gegenunendlich.de>
  *  Stephen Hurd <shurd@FreeBSD.org>
  *  Timothy Redaelli <drizzt@gufi.org>
  *  Tom Hukins <tom@FreeBSD.org>
  *  Vasil Dimov <vd@datamax.bg>
  *  Vladimir Chukharev
  *  Yanhui Shen <shen.elf@gmail.com>
  *  Zane C, Bowers <vvelox@vvelox.net>
  *  kmoore@FreeBSD.org

With hat:	portmgr