proto.c: Use IP-only match as fallback when mapping search result to hub
proto.c: Use IP-only match as fallback when mapping search result to hub

This fixes a bug with ncdc throwing away useful search results on NMDC
if the ip:port mentioned in the UDP packet doesn't exactly match the one
we're connected with.

The new behaviour is equivalent to DC++.

srijan/ncdc,Tilka/ncdc,srijan/ncdc,Tilka/ncdc,srijan/ncdc