Adds match_service() priority walk for fingerprinting:
1. port + http_regex confirmed
2. port + banner_regex confirmed
3. port:null + http_regex confirmed (custom-port services)
4. port-only fallback
http_regex is strict only once a probe has run; with no probe signals it
degrades to port-only matching, preserving pre-probe behaviour. match_port
kept as a probe-less alias.
ha-relevant: yes
Pouzor
b20c47a0a5