Do not create a hook manually for ubuntu-cpc builds, make-hooks does not like that.

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (2.618) UNRELEASED; urgency=medium
+
+  * Do not create a hook manually for ubuntu-cpc builds, make-hooks does not
+    like that.
+
+ -- Michael Hudson-Doyle <michael.hudson@ubuntu.com>  Wed, 09 Oct 2019 13:25:43 +1300
+
 livecd-rootfs (2.617) eoan; urgency=medium
 
   * Create the lxd group as a system group for all projects. (LP: #1844498)

live-build/auto/config

@@ -988,6 +988,7 @@ echo "BUILDSTAMP=\"$NOW\"" >> config/binary
 echo "SUBPROJECT=\"${SUBPROJECT:-}\"" >> config/binary
 echo "LB_DISTRIBUTION=\"$SUITE\"" >> config/binary
 
+if [ $PROJECT != ubuntu-cpc ]; then
     # We add the lxd group at image build time so that the default user
     # created by the installer or cloud-init is added to it (cloud-init
     # will create any group the user is configured to be added to, but as
@@ -999,6 +1000,7 @@ cat > config/hooks/100-add-lxd-group.chroot <<EOF
 echo "Adding lxd group..."
 addgroup --system --quiet lxd
 EOF
+fi
 
 case $ARCH+$SUBARCH in
 	armhf+raspi2|armhf+raspi3|arm64+raspi3)

live-build/ubuntu-cpc/hooks.d/chroot/025-create-groups.chroot

@@ -12,3 +12,6 @@ addgroup --system --quiet admin
 
 echo "Adding netdev group..."
 addgroup --system --quiet netdev
+
+echo "Adding lxd group..."
+addgroup --system --quiet lxd