[parrot/parrot] de92e5: update ticket links from trac to github

[GitHub]

  Branch: refs/heads/github-links
  Home:   https://github.com/parrot/parrot
  Commit: de92e5ef89c070f40dd81158ac9d9471caa3110b
      https://github.com/parrot/parrot/commit/de92e5ef89c070f40dd81158ac9d9471caa3110b
  Author: Moritz Lenz <moritz at faui2k3.org>
  Date:   2012-01-18 (Wed, 18 Jan 2012)

  Changed paths:
    M api.yaml
  M src/ops/sys.ops
  M t/pmc/exporter.t

  Log Message:
  -----------
  update ticket links from trac to github

Since many tickets have been closed before migrating, many trac URLs remain