x/ssh: filter debug and ignore messages in transport.readPacket.

This prevents these messages from confusing higher layers of the
protocol.

Fixes #16927.

Change-Id: If18d8d02bdde3c0470e29a7280cd355d3e55ad78
Reviewed-on: https://go-review.googlesource.com/34959
Run-TryBot: Han-Wen Nienhuys <hanwen@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Han-Wen Nienhuys <hanwen@google.com>
2 files changed