Bug 223298 - COPYRIGHT: Update description to make it fit to actual status of port tree

[Yasuhiro KIMURA]

Hello all.

I submitted following bug report.

Bug 223298 - COPYRIGHT: Update description to make it fit to actual status of port tree
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=223298

As is explained in comment of bug report, current COPYRIGHT file
describes as following.

* Copyright of the FreeBSD Ports Collection is held by The FreeBSD
  Project.
* The FreeBSD Ports Collection is distributed under the 2 clause BSD
  license.

But there are at least 2 exceptions that does not match above.

1. Files that explicitly claim their copyright holder and/or license
   terms in them. 
2. Patches obtained from upstream.

So I submitted patch to make description fit to real status. But there
may be other exceptional cases. So please let me know if you find it.
Then I will update patch to reflect it.

Best Regards.

---
Yasuhiro KIMURA