Comment 4 for bug 1471492

Short version: fixed locally, not a bug; /lib/lsb/init-functions.d/20-left-info-blocks got overwritten (Probably when creating an image of the hard drive) with some log info causing kernel upgrades to fail.

Long version:
This should probably be discarded; somehow, when I made a duplicate of the drive to upgrade to a larger hard drive, the '20-left-info-blocks' file in /lib/lsb/init-functions.d got overwritten somehow with part of a log file.
instead of what was supposed to be in there, there was:
[+0.01s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.01s] DEBUG: Starting Light Display Manager 1.14.0, UID=0 PID=987
[+0.01s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/60-gnome.conf
[+0.01s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.01s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.01s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.01s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.01s] DEBUG: Registered seat module xlocal
..and so forth, which obviously won't work, and caused the upgrade on the kernal to bomb, though it was od that the kernal appeared to be the only thing affected.
Once the file was replaced, and reinstalling linux-headers-generic, all appears to be well again. Hopefully I don't find more files overwritten in this manner.