detect: fix app-layer-protocol keyword for HTTP

detect: fix app-layer-protocol keyword for HTTP

Ticket: 4920

Completes commit c8dbe24fb6202550bbca1fab452ddbe864b2c9e2
which introduced AppProtoEquals to have a generic
check for http in signature can mean http1 or http2 in
traffic.

This commit missed this case, as I only looked for
git grep "alproto ==" and here we deal with
alproto_tc and alproto_ts, but not alproto by itself.