[webauthn] Merged Pull Request: Fix #561

emlun has just merged emlun's pull request 652 for https://github.com/w3c/webauthn:

== Fix #561 ==
@equalsJeffH How about this?


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[Preview](https://s3.amazonaws.com/pr-preview/w3c/webauthn/issue-561.html) | [Diff](https://s3.amazonaws.com/pr-preview/w3c/webauthn/ee174c2...b9575ef.html)

See https://github.com/w3c/webauthn/pull/652