packet: Allow SSH2_MSG_EXT_INFO when authenticated
When the server requests rekey, it can send the SSH2_MSG_EXT_INFO. This
message was being filtered out by the packet filtering. This includes a
test to enforce the filtering rules for this packet type.
Signed-off-by: Anderson Toshiyuki Sasaki <email@example.com>
Reviewed-by: Andreas Schneider <firstname.lastname@example.org>
(cherry picked from commit fe309ba43fb904da4385fc40a338ecc7482f8388)