packet: Adjust the packet filter to allow client-initialized rekey
If the rekey is initialized by client, it sends the first KEXINIT
message, changes to the INIT_SENT state and waits for the KEXINIT
message from the server. This was not covered in the current filter.
Signed-off-by: Jakub Jelen <email@example.com>
Reviewed-by: Daiki Ueno <firstname.lastname@example.org>
Reviewed-by: Andreas Schneider <email@example.com>