3df8f9c379
When chainloaded from another iPXE, there will be both a virtual filesystem and a managed network protocol available through which we could attempt to load autoexec.ipxe. Try both of these, with the virtual filesystem attempted first so that an autoexec.ipxe that was explicitly downloaded by the chainloading iPXE will have the highest priority. Signed-off-by: Michael Brown <mcb30@ipxe.org>