http2: fix minor stream accounting bug
http2: fix minor stream accounting bug

Update golang/go#18083

Change-Id: I2600f8a7a0d3a630003c010496a7fceca1b9f660
Reviewed-on: https://go-review.googlesource.com/33974
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

golang/net