Do not include curtin in the live-server installer.squashfs as the version of subiquity that includes it in the snap has now been released to stable.

debian/changelog

@@ -1,3 +1,11 @@
+livecd-rootfs (2.552) UNRELEASED; urgency=medium
+
+  * Do not include curtin in the live-server installer.squashfs as the
+    version of subiquity that includes it in the snap has now been released to
+    stable.
+
+ -- Michael Hudson-Doyle <michael.hudson@ubuntu.com>  Tue, 18 Dec 2018 15:17:08 +1300
+
 livecd-rootfs (2.551) disco; urgency=medium
 
   * Do no install openssh-server in the base filsystem for the live server

live-build/ubuntu-server/hooks/032-installer-squashfs.binary

@@ -49,12 +49,10 @@ EOF
 
 # Prepare installer layer.
 
-# Install any requirements for the installer, for things we don't want
-# to see on the installed system
-chroot $INSTALLER_ROOT apt-get -y install curtin lupin-casper
+# Install casper for live session magic.
+chroot $INSTALLER_ROOT apt-get -y install lupin-casper
 chroot $INSTALLER_ROOT apt-get clean
 
-
 # For bug #1743643 "Install to dirty disk with swap fails" remove the
 # "helpful" casper script that mounts any swap partitions it finds.
 rm -f $INSTALLER_ROOT/usr/share/initramfs-tools/scripts/casper-bottom/*swap