fix r3218: Initially building lists of ports, addresses, and server names had been placed at final configuration stage, because complete set of the "listen"s and the "server_names" were required for this operation. r3218 broke it, because the "listen"s go usually first in configuration, and cscf->server_names is empty at this stage, therefore no virtual names were configured. Now server configurations are stored in array for each address:port to configure virtual names. Also regex captures flag is moved from server names to core server configuration.