hdt: Adding dump_filename= option

hdt: Adding dump_filename= option

This option allow the user to redefine the way filename is made-of.
By default that's "mac_address+dmi_vendor_name+dmi_product_name"

This can be overidded by the following syntax:

dump_filename=your_filename

Note that it's mandatory not to add "" or '' around your_filename.

your_filename could be a regular filename but can also includes %{}
directives as defined by :
%{m} = mac address
%{v} = vendor name of the machine
%{p} = product name of the machine
%{ba} = Asset tag of the base board
%{bs} = Serial number of the base board
%{ca} = Asset tag of the chassis
%{cs} = Serial number of the chassis
%{sk} = SKU number of the system
%{ss} = Serial number of the system

Here come a possible command line :
APPEND nomenu auto='dump;' dump_path=hdt2 tftp_ip=192.168.1.254 dump_filename=%{m}+%{bs}+%{ba}+%{cs}+%{ca}+%{sk}+%{ss}+%{p}+%{v}