Revert "Revert "Purge the unattended-upgrades pkg""

This reverts commit 5f00dd0752c262e01a0a2886a02e8cee22493251.

Change-Id: I50c5eff4ba765915b20e7713c4f365ab8ae8d2d1
diff --git a/tcp_tests/templates/shared-salt.yaml b/tcp_tests/templates/shared-salt.yaml
index 95f207a..2d06193 100644
--- a/tcp_tests/templates/shared-salt.yaml
+++ b/tcp_tests/templates/shared-salt.yaml
@@ -62,7 +62,8 @@
     echo "{{ UBUNTU_REPOSITORY }}" > /etc/apt/sources.list.d/ubuntu.list
     echo "{{ UBUNTU_UPDATES_REPOSITORY }}" > /etc/apt/sources.list.d/ubuntu_updates.list
     echo "{{ UBUNTU_SECURITY_REPOSITORY }}" > /etc/apt/sources.list.d/ubuntu_security.list
-    eatmydata apt-get clean && apt-get update;
+    eatmydata apt-get clean;
+    apt-get update;
     sync;
   node_name: {{ NODE_NAME }}
   retry: {count: 1, delay: 5}