lua: extend SCFlowAppLayerProto

lua: extend SCFlowAppLayerProto

Change SCFlowAppLayerProto to return 5 values:
<alproto> <alproto_ts> <alproto_tc> <alproto_orig> <alproto_expect>:

alproto: detected protocol
alproto_ts: detected protocol in toserver direction
alproto_tc: detected protocol in toclient direction
alproto_orig: pre-change/upgrade protocol
alproto_expected: expected protocol in change/upgrade

Orig and expect are used when changing and upgrading protocols. In a
SMTP STARTTLS case, orig would normally be set to "smtp" and expect
to "tls".