fix legacy grub image to match path on the autoinstall servers

files/grub2/i386-pc/bswap_test.mod

files/grub2/i386-pc/btrfs.mod

files/grub2/i386-pc/bufio.mod

files/grub2/i386-pc/cat.mod

files/grub2/i386-pc/cbfs.mod

files/grub2/i386-pc/cbls.mod

files/grub2/i386-pc/cbmemc.mod

files/grub2/i386-pc/cbtable.mod

files/grub2/i386-pc/cbtime.mod

files/grub2/i386-pc/chain.mod

files/grub2/i386-pc/cmdline_cat_test.mod

files/grub2/i386-pc/cmosdump.mod

files/grub2/i386-pc/cmostest.mod

files/grub2/i386-pc/cmp.mod

files/grub2/i386-pc/cmp_test.mod

files/grub2/i386-pc/command.lst

files/grub2/i386-pc/configfile.mod

files/grub2/i386-pc/core.0

files/grub2/i386-pc/cpio.mod

files/grub2/i386-pc/cpio_be.mod