[w3c/webauthn] 3938fc: Address review comments by @akshayku

  Branch: refs/heads/issue-720-user-handle-optional
  Home:   https://github.com/w3c/webauthn
  Commit: 3938fc136da36ba518809b7ba9df476360173cf0
      https://github.com/w3c/webauthn/commit/3938fc136da36ba518809b7ba9df476360173cf0
  Author: Emil Lundberg <emil@yubico.com>
  Date:   2017-12-25 (Mon, 25 Dec 2017)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  Address review comments by @akshayku


  Commit: 609d28a34bc5ff9b96c10f17db308268f9aa4ec5
      https://github.com/w3c/webauthn/commit/609d28a34bc5ff9b96c10f17db308268f9aa4ec5
  Author: Emil Lundberg <emil@yubico.com>
  Date:   2017-12-25 (Mon, 25 Dec 2017)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  CTAP alignment: Make storing user handle optional for non-resident keys

CTAP's [authenticatorMakeCredential][1] method stores the `user`
parameter only for resident credentials.

[1]: https://fidoalliance.org/specs/fido-v2.0-rd-20170927/fido-client-to-authenticator-protocol-v2.0-rd-20170927.html#h3_authenticatorMakeCredential


  Commit: 684581f714e3a4c10f07f63db5233751e9bbf3a2
      https://github.com/w3c/webauthn/commit/684581f714e3a4c10f07f63db5233751e9bbf3a2
  Author: Emil Lundberg <emil@yubico.com>
  Date:   2017-12-25 (Mon, 25 Dec 2017)

  Changed paths:
    M index.bs

  Log Message:
  -----------
  Revert "Don't say user handle is optional in Public Key Credential Source definition"

This reverts commit d448eb3a2da0b5682cdf98c10c6a3ee5d399d667.


Compare: https://github.com/w3c/webauthn/compare/3b2a1d141cbd...684581f714e3