lightdm start kills /etc/ini.d/rc after unattended (preseeded) install

[Kurt Hutchison]

We support unattended installs of Ubuntu using the preseed method.

When testing Ubuntu 14.10 desktop we noticed that after an unattended install
/etc/init.d/rc would exit after /etc/init.d/lightdm start was called.
This is repeateable after a reboot, do an unattended install, and then modiy /etc/init.d/rc
to log each startup script invocation to a file, you will see that lightdm is the last script to run.
In particular /etc/init.d/rc.local does not run when switching to run level 2, which is how we noticed it.

Adding a --background flag to the start-stop-daemon call in /etc/init.d/lightdm works around this issue
and does not seem to hurt anything.

That may not be the correct fix, but it is a work-around.

It appears a signal is generated from lightdm that goes through the controlling tty
and kills /etc/init.d/rc. --background stops that from happening.

I was unable to determine why it only happens after an unattended install.
There are other known issues with unattended install in 14.10 that may or may not be related.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: lightdm 1.12.1-0ubuntu1
ProcVersionSignature: Ubuntu 3.16.0-23.31-generic 3.16.4
Uname: Linux 3.16.0-23-generic i686
ApportVersion: 2.14.7-0ubuntu8
Architecture: i386
CurrentDesktop: Unity
Date: Mon Nov 3 10:05:04 2014
InstallationDate: Installed on 2014-10-30 (4 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Release i386 (20141022.1)
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.init.d.lightdm: [modified]
mtime.conffile..etc.init.d.lightdm: 2014-10-30T08:49:42.799999