Currently dev unstable ISOs after installation come up with GRUB even though they should have a silent timeout as we prefer grub to not show up unless there's multiple OSes to pick from.

This is broken because for some reason the post install cleanup of calamares rips out grub-efi-amd64-bin:

Start-Date: 2017-12-12  06:30:03
Commandline: apt-get --purge -q -y autoremove
Purge: libkpmcore7:amd64 (3.2.1+p16.04+git20171207.0145-0), libboost-python1.58.0:amd64 (1.58.0+dfsg-5ubuntu3.1), libparted-fs-resize0:amd64 (3.2-15), kpmcore:amd64 (3.2.1+p16.04+git20171207.0145-0), grub-efi-amd64-bin:amd64 (2.02~beta2-36ubuntu3.14), libyaml-cpp0.5v5:amd64 (0.5.2-3)
End-Date: 2017-12-12  06:30:05

which in turn deletes /etc/default/grub which is where the hidden timeout should come from. Leading to a badly configured grub.

The package seems to be originally pulled into the ISO by live-build

Start-Date: 2017-12-10  08:29:02
Commandline: apt-get --yes install lupin-casper linux-signed-generic-hwe-16.04 neon-live
Install: python-tdb:amd64 (1.3.8-2, automatic), calamares-settings:amd64 (0+p16.04+git20170914.0828, automatic), python-samba:amd64 (2:4.3.11+dfsg-0ubuntu0.16.04.12, automatic), libkpmcore7:amd64 (3.2.1+p16.04+git20171207.0145-0, automatic), casper:amd64 (1.376.2, automatic), linux-signed-generic-hwe-16.04:amd64 (4.10.0.42.44), lupin-casper:amd64 (0.57), libboost-python1.58.0:amd64 (1.58.0+dfsg-5ubuntu3.1, automatic), reiserfsprogs:amd64 (1:3.6.24-3.1, automatic), jfsutils:amd64 (1.1.15-2.1, automatic), calamares:amd64 (3.1.0+p16.04+git20171205.1541-0, automatic), linux-signed-image-4.10.0-42-generic:amd64 (4.10.0-42.46~16.04.1, automatic), libparted-fs-resize0:amd64 (3.2-15, automatic), cifs-utils:amd64 (2:6.4-1ubuntu1.1, automatic), linux-signed-image-generic-hwe-16.04:amd64 (4.10.0.42.44, automatic), kpmcore:amd64 (3.2.1+p16.04+git20171207.0145-0, automatic), localechooser-data:amd64 (2.65ubuntu4, automatic), python-crypto:amd64 (2.6.1-6ubuntu0.16.04.2, automatic), user-setup:amd64 (1.63ubuntu4, automatic), neon-live:amd64 (4+p16.04+git20171209.1042), grub-efi-amd64-bin:amd64 (2.02~beta2-36ubuntu3.14, automatic), xfsprogs:amd64 (4.3.0+nmu1ubuntu1.1, automatic), samba-common:amd64 (2:4.3.11+dfsg-0ubuntu0.16.04.12, automatic), samba-common-bin:amd64 (2:4.3.11+dfsg-0ubuntu0.16.04.12, automatic), btrfs-tools:amd64 (4.4-1ubuntu1, automatic), python-ldb:amd64 (2:1.1.24-1ubuntu3, automatic), keyutils:amd64 (1.5.9-8ubuntu1, automatic), libyaml-cpp0.5v5:amd64 (0.5.2-3, automatic)
End-Date: 2017-12-10  08:29:19

I am somewhat confident that either live-build or cala needs to `apt-mark manual` the grub packages to prevent them from getting autoremoved. Seeing as this works with ubiquity I am thinking that calamares needs to do that (i.e. iff one were to install on a !efi system the efi package should get autoremoved, whereas on an efi system the !efi package should get autoremoved. A decision which is only really to be made at installation time).