[w3c/webauthn] c79e21: IDL cleanup: don't require callers to create Crede...

  Branch: refs/heads/vgb-credentialObjectKeep
  Home:   https://github.com/w3c/webauthn
  Commit: c79e21b6ad5804e84bbee4983706366455000494
      https://github.com/w3c/webauthn/commit/c79e21b6ad5804e84bbee4983706366455000494
  Author: Vijay Bharadwaj <vijaybh@users.noreply.github.com>
  Date:   2016-08-04 (Thu, 04 Aug 2016)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  IDL cleanup: don't require callers to create Credential objects

This is the minimal version of the change required to fix the IDL issue
that @jcjones brought up regarding Credential objects. Unlike PR #158,
it retains the credential type and leaves the actual API surface and
samples unchanged.

If we pick this approach, PR #158 can be closed out and will no longer
be necessary.