Depend on pxz and vmdk-stream-converter instead of installing them at runtime

debian/control

@@ -25,6 +25,7 @@ Depends: ${misc:Depends},
          lzma,
          parted,
          procps,
+         pxz,
          python-minimal | python,
          python3-software-properties,
          qemu-utils,
@@ -33,6 +34,7 @@ Depends: ${misc:Depends},
          squashfs-tools (>= 1:3.3-1),
          sudo,
          ubuntu-image,
+         vmdk-stream-converter [amd64 i386],
          zerofree
 Suggests: partimage
 Breaks: ubuntu-defaults-builder (<< 0.32)

live-build/auto/build

@@ -17,8 +17,6 @@ fi
 
 if [ "${IMAGEFORMAT:-}" = "ubuntu-image" ]; then
 	# Use ubuntu-image instead of live-build
-	apt-get install -qqy pxz
-
 	env SNAPPY_STORE_NO_CDN=1 \
 	ubuntu-image -c edge \
 		-o livecd."$PROJECT".img livecd."$PROJECT".model-assertion

live-build/functions

@@ -226,7 +226,6 @@ create_vmdk() {
     destination="$2"
     size="${3:-10240}"
 
-    apt-get install -qqy vmdk-stream-converter
     streamconverter="/usr/share/pyshared/VMDKstream.py"
     scratch_d=$(mktemp -d)
     cp ${src} ${scratch_d}/resize.img

live-build/ubuntu-cpc/hooks/040-qcow2-image.binary

@@ -13,7 +13,6 @@ case $ARCH:$SUBARCH in
 	# Not sure if any other cloud images use subarch for something that
 	# should take qcow2 format, so only skipping this on raspi2 for now.
 	armhf:raspi2)
-		apt-get install -qqy pxz
 		pxz -T4 -c binary/boot/disk.ext4 > livecd.ubuntu-cpc.disk1.img.xz
 	        exit 0
 		;;