Fix default sni

[sarge]

When requesting without SNI, the default connection policy needs to know to use the fallback certificate.

// arrange
caddytest.InitServer(t, ` 
  {
    http_port     9080
    https_port    9443
    default_sni   *.caddy.localhost
  }
  
  127.0.0.1:9443 {
    tls /caddy.localhost.crt /caddy.localhost.key {
    }
    respond /version 200 {
      body "hello from a.caddy.localhost"
    }	
  }
  `, "caddyfile")

	// act and assert
	caddytest.AssertGetResponse(t, "https://127.0.0.1:9443/version", 200, "hello from a.caddy.localhost")

[mholt]

Going to try to re-jigger the CI to attach, but I doubt it'll work...

Edit: Nope, ha...

[mholt]

In lieu of missing CI attachments, I cloned this locally and ran the tests, and it LGTM!

Thanks @sarge !