Comment 28 for bug 1536810

Verified fixed in arm64 image for 20160227.
I noticed it does still have the bogus 'initrd.img file:
$ ls -l $exdir/boot
total 20592
drwxr-xr-x 2 root root 4096 Feb 27 14:36 grub
-rw-r--r-- 1 root root 21079648 Feb 27 14:38 initrd.img

But the initrd.img file does not seem to cause a problem here, and after install we have a symlink to the proper place.
$ ls -l $exdir/boot/initrd.img
lrwxrwxrwx 1 root root 26 Mar 1 15:13 /tmp/tmp.RGUZJZwhWr/boot/initrd.img -> initrd.img-4.4.0-8-generic

I've reverted my workaround change in maas-images at revno 284.