ocsp: remove incorrect iota and update docs on CreateRequest
ocsp: remove incorrect iota and update docs on CreateRequest

Change-Id: Ib347b468035d699156b6bff6c30fb653a1c5804d
Reviewed-on: https://go-review.googlesource.com/71755
Reviewed-by: Joe Tsai <7277d7402195d5c2006c89f45718cf82bb3e527f@gmail.com>

golang/crypto,ScriptRock/crypto,golang/crypto,ScriptRock/crypto,golang/crypto