Bug#777647: partman-efi always complains when installing from usb

[Phillip Susi <phillsusi@gmail.com>]

Package: partman-efi
Version: 59

partman-efi uses flawed logic that trips up when installing from usb.
init.d/efi scans the system and counts the number of efi system
partitions, and the number of non efi system partitions.  If it does not
find an EFI system partition, but does find at least one non ESP, then
it throws the non_efi_system warning/question.  The problem is that when
installing to a disk that does not already have an efi system partition,
the script *always* detects a non EFI system partition, and throws the
warning.  This may be connected to a recent change in libparted.
Looking at the partman logs and the output after adding a set -x to the
init.d/efi script, it appears to me that what is happening is that the
system asks libparted to create a new partition on the hard disk that
will become an EFI system partition.  Either init.d/efi runs before the
partition has been formatted with a fat filesystem, or parted_server is
still running and is keeping the "ext2" fs type cached from before it
was formatted.  Either way, the script decides it sees an ext2
filesystem on the drive, and that counts as a non EFI system partition,
and so it throws the message.

Forwarding this from launchpad bug #1418706 in Ubuntu.