qlog: Update ConnectionClose with CryptoError

[evanrittenhouse]

This makes the qlog crate fit the specification laid out in https://github.com/quicwg/qlog/pull/392.

This yields the following ConnectionClose frame:

{"time":5.063584,"name":"transport:packet_sent","data":{"header":{"packet_type":"1RTT","packet_number":5},"raw":{"length":49,"payload_length":11},"send_at_time":5.063584,"frames":[{"frame_type":"connection_close","error_space":"application_error","error_code":256,"reason":"kthxbye"}]}}

We won't be able to log CryptoErrors without a larger change that pushes detection of connection establishment into the qlog crate. We could also explore logging one of two different ConnectionClose events on close, one each for pre- and post-establishment, but that seemed messy. I can implement that if we do want to go down that route.