Import patches-unapplied version 2.459 to ubuntu/artful-proposed

Imported using git-ubuntu import.

Changelog parent: e4b41272e2

New changelog entries:
  [ Steve Langasek ]
  * Remove spurious call to 'sync'; we don't need to flush all disk caches
    on the system to cleanly unmount a partition.
  [ Michael Hudson-Doyle ]
  * only show alert (i.e. panic) kernel messages on the console when
    subiquity is running

debian/changelog

@@ -1,3 +1,15 @@
+livecd-rootfs (2.459) artful; urgency=medium
+
+  [ Steve Langasek ]
+  * Remove spurious call to 'sync'; we don't need to flush all disk caches
+    on the system to cleanly unmount a partition.
+
+  [ Michael Hudson-Doyle ]
+  * only show alert (i.e. panic) kernel messages on the console when
+    subiquity is running
+
+ -- Michael Hudson-Doyle <michael.hudson@ubuntu.com>  Thu, 21 Sep 2017 11:34:20 +1200
+
 livecd-rootfs (2.458) artful; urgency=medium
 
   * Move default netplan config for server-live image to where hook will

live-build/ubuntu-cpc/hooks/033-disk-image-uefi.binary

@@ -110,7 +110,6 @@ install_grub() {
     chroot mountpoint apt-get -y clean
 
     rm mountpoint/tmp/device.map
-    sync
     umount mountpoint/boot/efi
     mount
     umount_partition mountpoint

live-build/ubuntu-server/includes.binary/overlay/lib/systemd/system/subiquity.service

@@ -10,6 +10,7 @@ ConditionPathExists=!/run/subiquity/complete
 [Service]
 Environment=PYTHONPATH=/usr/share/subiquity
 ExecStartPre=/bin/systemctl stop getty@tty1
+ExecStartPre=/bin/dmesg -n 1
 ExecStart=/sbin/agetty -n --noclear -l /snap/bin/subiquity tty1 $TERM
 ExecStopPost=/bin/systemctl start getty@tty1
 Type=idle