Update from Wily to Xenial fails on plymouth themes

[Andrea Bernabei]

The title probably needs adjusting...

I had an issue while updating a Wily setup to Xenial using
do-release-upgrade -d

Please find the full log (minus some of the pkg download lines) here
http://paste.ubuntu.com/14486461/

A few highlights from the log (in temporal order):

- line 1441
Processing triggers for plymouth-theme-ubuntu-text (0.9.0-0ubuntu9) ...
update-initramfs: deferring update (trigger activated)

- line 1524
Preparing to unpack .../plymouth-theme-ubuntu-text_0.9.2-3ubuntu9_amd64.deb ...
Unpacking plymouth-theme-ubuntu-text (0.9.2-3ubuntu9) over (0.9.0-0ubuntu9) ...
dpkg: warning: unable to delete old directory '/lib/plymouth/themes/ubuntu-text': Directory not empty
Preparing to unpack .../plymouth_0.9.2-3ubuntu9_amd64.deb ...
Unpacking plymouth (0.9.2-3ubuntu9) over (0.9.0-0ubuntu9) ...
dpkg: warning: unable to delete old directory '/lib/plymouth/themes': Directory not empty
dpkg: warning: unable to delete old directory '/lib/plymouth': Directory not empty

- line 6911
Setting up linux-image-4.3.0-5-generic (4.3.0-5.16) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Examining /etc/kernel/postinst.d.
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.3.0-5-generic /boot/vmlinuz-4.3.0-5-generic
run-parts: executing /etc/kernel/postinst.d/dkms 4.3.0-5-generic /boot/vmlinuz-4.3.0-5-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.3.0-5-generic /boot/vmlinuz-4.3.0-5-generic
update-initramfs: Generating /boot/initrd.img-4.3.0-5-generic
sed: can't read /usr/share/plymouth/themes/ubuntu-text/ubuntu-text.plymouth: No such file or directory
E: /usr/share/initramfs-tools/hooks/plymouth failed with return 2.
update-initramfs: failed for /boot/initrd.img-4.3.0-5-generic with 2.
run-parts: /etc/kernel/postinst.d/initramfs-tools exited with return code 2
Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-4.3.0-5-generic.postinst line 1025.
dpkg: error processing package linux-image-4.3.0-5-generic (--configure):
 subprocess installed post-installation script returned error exit status 2

- line 7273
dpkg: dependency problems prevent configuration of linux-image-extra-4.3.0-5-generic:
 linux-image-extra-4.3.0-5-generic depends on linux-image-4.3.0-5-generic; however:
  Package linux-image-4.3.0-5-generic is not configured yet.

dpkg: error processing package linux-image-extra-4.3.0-5-generic (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.

- line 7486
Setting up plymouth-theme-ubuntu-text (0.9.2-3ubuntu9) ...
update-alternatives: warning: alternative /lib/plymouth/themes/ubuntu-text/ubuntu-text.plymouth (part of link group text.plymouth) doesn't exist; removing from list of alternatives
update-alternatives: warning: /etc/alternatives/text.plymouth is dangling; it will be updated with best choice
update-alternatives: renaming text.plymouth link from /lib/plymouth/themes/text.plymouth to /usr/share/plymouth/themes/text.plymouth
update-alternatives: using /usr/share/plymouth/themes/ubuntu-text/ubuntu-text.plymouth to provide /usr/share/plymouth/themes/text.plymouth (text.plymouth) in auto mode
update-initramfs: deferring update (trigger activated)