HTTP/2 Frame to HttpObject Adapter

Transferring @Scottmitch's personal pull request to @akamai's fork for https://github.com/netty/netty/pull/2695
I don't believe so.  The `clientObserver` was declared as a mock but then never used.  All of the messages are expected/verified at the `serverObserver` which is also used on the server side of the connection.  Based upon the logic of the test they are not checking (or sending) to the client anyways and so this has no impact, and the logic checking may be convoluted if the `serverObserver` is used to verify a message on the server, but that actually was received on the client. It looked like copy/paste error to me. @nmittler - does this look OK?