Description of problem:
to get the kickstart file with http, a user has to supply the entire URL.
loader should be enhanced to get the servername and filename from dhcp and
construct the URL with these values (like the NFS method).

How reproducible:
Always

Steps to Reproduce:
it's great that loader can now get the kickstart file with http, but it
requires that user input the URL on the syslinux.cfg command line. (the
code segment below shows that the function kickstartFromHttp() will return
if no kickstart file is supplied).

================================================
current kickstartFromHttp()
================================================
    if (ksSource) {
        ksPath = alloca(strlen(ksSource) + 1);
        strcpy(ksPath, ksSource);
    } else {
        logMessage("no location specified");
        return 1;
    }
================================================


it would be better if loader could build a URL from the dhcp response if no
URL is specified.

================================================
potential enhancement to kickstartFromHttp()
================================================
    if (ksSource) {
        ksPath = alloca(strlen(ksSource) + 1);
        strcpy(ksPath, ksSource);
    } else {
        /*
         * build the path to the kickstart file from the DHCP response
         */
        ksPath = alloca(strlen(file) +
                        strlen(inet_ntoa(netDev.dev.nextServer)) + 70);
        strcpy(ksPath, inet_ntoa(netDev.dev.nextServer));
        strcat(ksPath, file);
    }
=============================================