Import patches-unapplied version 2.447 to ubuntu/artful-proposed

Imported using git-ubuntu import.

Changelog parent: 1a48d101d5

New changelog entries:
  * Add cm3 as a known ubuntu-core image type.  LP: #1698223.

debian/changelog

@@ -1,3 +1,9 @@
+livecd-rootfs (2.447) artful; urgency=medium
+
+  * Add cm3 as a known ubuntu-core image type.  LP: #1698223.
+
+ -- Steve Langasek <steve.langasek@ubuntu.com>  Thu, 15 Jun 2017 23:36:44 -0700
+
 livecd-rootfs (2.446) artful; urgency=medium
 
   * Build ubuntu back with tasks. The metapackage switch was due to g++

live-build/auto/config

@@ -162,6 +162,8 @@ case $IMAGEFORMAT in
 				MODEL=pi2 ;;
 			armhf+raspi3)
 				MODEL=pi3 ;;
+			armhf+cm3)
+				MODEL=cm3 ;;
 			*)
 				echo "Model $ARCH+${SUBARCH:-} unknown to livecd-rootfs" >&2
 				exit 1