If you've enabled the server-status tool in apache, you may see many entries that look like this:
37-0 - 0/0/9 Â . 0.00 24325 0 Â 0.0 0.00 0.18 1.2.3.4Â localhost NULL
39-0 - 0/0/8 Â . 0.00 24324 65 Â 0.0 0.00 0.15 2.3.4.5Â localhost NULL
40-0 - 0/0/15 Â . 0.00 24306 179 0.0 0.00 0.34 3.4.5.6Â localhost NULL
41-0 - 0/0/110 . 1.10 23858 48 Â 0.0 0.00 0.54 4.5.6.7Â localhost NULL
After the client loads his first page, knowing that the client will likely click a link, the browser will connect to your server before the client has clicked anything. Â For these cases, no request has yet been made... it's just an empty, idle connection without any communication over it yet (until a click happens).
Since the "Host" header has not yet been sent, Apache won't know which VirtualHost to send the request to, so it defaults to the very first VirtualHost on that IP, which in this case, is in /etc/httpd/conf/httpd-vhosts.conf, as it uses a ServerName of "localhost", since nothing specific seems approriate. (it could also be in the /etc/httpd/conf/ips.conf for a shared IP)