Fix two QUIC issues:

Fix two QUIC issues:

  1) We treated stream reset like connection terminated, which
     is just wrong.  We should send EOF to the stream but leave
     the connection alone.

  2) When we got an unexpected EOF on a stream, we raised the
     exception in the wrong place, killing the QUIC connection
     but leaving the stream blocked.  Now we deliver the exception
     to the stream and don't kill the connection.