[zanata/zanata-server] ec5102: doc(CONTRIBUTING): update according to commenets

[GitHub]

  Branch: refs/heads/contributing
  Home:   https://github.com/zanata/zanata-server
  Commit: ec51021e7bbb7a944fbf53062f1b9073c04c009d
      https://github.com/zanata/zanata-server/commit/ec51021e7bbb7a944fbf53062f1b9073c04c009d
  Author: Ding-Yi Chen <dingyichen at gmail.com>
  Date:   2016-02-25 (Thu, 25 Feb 2016)

  Changed paths:
    M CONTRIBUTING.md

  Log Message:
  -----------
  doc(CONTRIBUTING): update according to commenets