[zanata/zanata-server] c34abe: update documentation

[GitHub]

  Branch: refs/heads/replace-seam-security
  Home:   https://github.com/zanata/zanata-server
  Commit: c34abe1b313ade1815c2d17dbc499a91e0e304ae
      https://github.com/zanata/zanata-server/commit/c34abe1b313ade1815c2d17dbc499a91e0e304ae
  Author: Patrick Huang <pahuang at redhat.com>
  Date:   2015-08-04 (Tue, 04 Aug 2015)

  Changed paths:
    M docs/user-guide/system-admin/configuration/authentication.md

  Log Message:
  -----------
  update documentation