Add bzip2 to test install

I think this has gone missing on test nodes during unpuppeting.  Add,
as the gentoo job grabs some bz2 tarballs for extraction.

Change-Id: Icb82930702124f7bf112b03a469d90d4163d398b

tests/install_test_deps.sh

@@ -6,6 +6,7 @@ set -o pipefail
 sudo apt-get update || true
 sudo apt-get install -y --force-yes \
         apt-transport-https \
+        bzip2 \
         debootstrap \
         docker.io \
         inetutils-ping \
@@ -17,12 +18,14 @@ sudo apt-get install -y --force-yes \
         uuid-runtime \
         yum-utils || \
     sudo yum -y install \
+        bzip2 \
         debootstrap \
         docker \
         kpartx \
         util-linux \
         qemu-img || \
     sudo emerge \
+        app-arch/bzip2 \
         app-emulation/qemu \
         dev-python/pyyaml \
         sys-block/parted \