H2->H1 downgrades trigger a retry over H2 first

[nox]

curl 'https://roaming.officeapps.live.com/rs/v1/settings/1065?rs=en-US' -X OPTIONS -v

*   Trying 52.109.88.174:443...
* Connected to roaming.officeapps.live.com (52.109.88.174) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use h2
* Server certificate:
*  subject: CN=roaming.officeapps.live.com
*  start date: Oct  6 18:18:00 2020 GMT
*  expire date: Oct  6 18:18:00 2021 GMT
*  subjectAltName: host "roaming.officeapps.live.com" matched cert's "*.officeapps.live.com"
*  issuer: C=US; O=Microsoft Corporation; CN=Microsoft RSA TLS CA 02
*  SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x7fc64b00d400)
> OPTIONS /rs/v1/settings/1065?rs=en-US HTTP/2
> Host: roaming.officeapps.live.com
> user-agent: curl/7.75.0
> accept: */*
> 
* Connection state changed (MAX_CONCURRENT_STREAMS == 100)!
* HTTP/2 stream 0 was not closed cleanly: HTTP_1_1_REQUIRED (err 13)
* Downgrades to HTTP/1.1!
* Empty reply from server
* Connection #0 to host roaming.officeapps.live.com left intact
* Issue another request to this URL: 'https://roaming.officeapps.live.com/rs/v1/settings/1065?rs=en-US'
* Found bundle for host roaming.officeapps.live.com: 0x7fc649f05ce0 [can multiplex]
* Re-using existing connection! (#0) with host roaming.officeapps.live.com
* Connected to roaming.officeapps.live.com (52.109.88.174) port 443 (#0)
* Using Stream ID: 3 (easy handle 0x7fc64b00d400)
> OPTIONS /rs/v1/settings/1065?rs=en-US HTTP/2
> Host: roaming.officeapps.live.com
> user-agent: curl/7.75.0
> accept: */*
> 
* HTTP/2 stream 0 was not closed cleanly: HTTP_1_1_REQUIRED (err 13)
* Connection died, retrying a fresh connect(retry count: 1)
* Downgrades to HTTP/1.1!
* Closing connection 0
* Issue another request to this URL: 'https://roaming.officeapps.live.com/rs/v1/settings/1065?rs=en-US'
* Hostname roaming.officeapps.live.com was found in DNS cache
*   Trying 52.109.88.174:443...
* Connected to roaming.officeapps.live.com (52.109.88.174) port 443 (#1)
* ALPN, offering http/1.1
* SSL re-using session ID
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* old SSL session ID is stale, removing
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
*  subject: CN=roaming.officeapps.live.com
*  start date: Oct  6 18:18:00 2020 GMT
*  expire date: Oct  6 18:18:00 2021 GMT
*  subjectAltName: host "roaming.officeapps.live.com" matched cert's "*.officeapps.live.com"
*  issuer: C=US; O=Microsoft Corporation; CN=Microsoft RSA TLS CA 02
*  SSL certificate verify ok.
> OPTIONS /rs/v1/settings/1065?rs=en-US HTTP/1.1
> Host: roaming.officeapps.live.com
> User-Agent: curl/7.75.0
> Accept: */*
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 204 No Content
< Cache-Control: no-cache
< Pragma: no-cache
< Content-Type: application/json; charset=utf-8
< Expires: -1
< Server: Microsoft-IIS/10.0
< X-OfficeFE: RoamingFE_IN_1
< X-OfficeVersion: 16.0.13914.30575
< X-OfficeCluster: weu-roaming.officeapps.live.com
< X-CorrelationId: 3bf5bf83-e562-4b74-b46c-396b4cf8bbfc
< X-Powered-By: ASP.NET
< Date: Mon, 22 Mar 2021 11:30:27 GMT
< 
* Excess found: excess = 384 url = /rs/v1/settings/1065 (zero-length body)
* Connection #1 to host roaming.officeapps.live.com left intact

Note how it says "* Downgrades to HTTP/1.1!" twice.