MAAS UI could warn about missing EFI partition

[Junien F]

Hi,

When creating a disk / partitions layout in MAAS, no warning is given if one forgets to create a dedicated fat32 /boot/efi partitions. This makes deployments fail with (at least for Ubuntu 16.04) :

+ grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=ubuntu --recheck
Installing for x86_64-efi platform.
grub-install: error: failed to get canonical path of `/boot/efi'.
failed to install grub!

I feel like MAAS could/should warn the user when he's modifying the disk layout and not creating this partition, if the node is EFI.

This is with MAAS 2.3.0-6434-gd354690-0ubuntu1~16.04.1

Thanks