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Only HTTP/1.1 (and below) sockets may renegotiate. This fix a
crash because SpdyHttpStream didn't account for this properly.
(And can't as the renego + client auth hack is inherently
incompatible with multiplexing.)

Tested manually against hacked up Go servers:

- HTTP/1.1 server which renegotiates with client auth before
  sending a response on a fresh socket.

- Same as above but with a reused socket (the server only
  requests renego when fetching /auth).

- HTTP/2 which incorrectly renegotiates with client auth upon
  requesting /auth. Verified that we get ERR_SSL_PROTOCOL_ERROR
  and not crash.

- HTTP/1.1 server which does two handshakes in a row with Finished
  and HelloRequest in the same record. NSS and BoringSSL differ in
  their behavior here, but in neither port should we miss the
  renego.

BUG=484543,462283

Review URL: https://codereview.chromium.org/1131763002

Cr-Commit-Position: refs/heads/master@{#329466}