[w3c/webauthn] 745363: GitHub pages bugfix: Pull in `bikeshed-template` P...

  Branch: refs/heads/travisci_fix
  Home:   https://github.com/w3c/webauthn
  Commit: 7453638de64a202b9227da9566b1d023938d78a9
      https://github.com/w3c/webauthn/commit/7453638de64a202b9227da9566b1d023938d78a9
  Author: J.C. Jones <jjones@mozilla.com>
  Date:   2016-04-13 (Wed, 13 Apr 2016)

  Changed paths:
    M lib/id.mk

  Log Message:
  -----------
  GitHub pages bugfix: Pull in `bikeshed-template` PR detection fix

PRs were being incorrectly detected after a TravisCI environment variable
change that happened some time ago. This updates the logic to be more robust.