bootp: Process DHCPACK packet during HTTP Boot

bootp: Process DHCPACK packet during HTTP Boot

The vendor class identifier with the string "HTTPClient" is used to
denote the packet as responding to HTTP boot request.  In DHCP4 config,
the filename for HTTP boot is the URL of the boot file, while for PXE
boot it is the path to the boot file.  As a consequence, the next-server
becomes obselete because the HTTP URL already contains the server
address for the boot file.  For DHCP6 config, there's no difference
definition in existing config as dhcp6.bootfile-url can be used to
specify URL for both HTTP and PXE boot file.

Add processing for "HTTPClient" vendor class identifier in DHCPACK
packet by treating it as HTTP format, not as the PXE format.

Signed-off-by: Michael Chang <mchang@suse.com>
Signed-off-by: Ken Lin <ken.lin@hpe.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Gbp-Pq: Topic network
Gbp-Pq: Name bootp-process-dhcpack-http-boot.patch