fix r3218:

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.