Install missing packages in nodepool instance

The 'rpm', 'yumdownloader' and 'bc' tools do not come installed in the
Ubuntu nodepool image. We need 'rpm' and 'yumdownloader' to build
centos-minimal amphora images and 'bc' for checking minimum supported
Ubuntu version in diskimage-create.sh

This patch also adds octavia-lib to the required projects.

Change-Id: Iaa0f763005529cc394d3b95ce07f2be71e9b3778

playbooks/image-build/run.yaml

@@ -18,6 +18,9 @@
         - python-yaml
         - debootstrap
         - qemu
+        - bc
+        - rpm
+        - yum-utils
     - name: Install required pip packages
       pip:
         name: "{{  item }}"

zuul.d/jobs.yaml

@@ -31,6 +31,7 @@
     required-projects:
         - openstack/diskimage-builder
         - openstack/octavia
+        - openstack/octavia-lib
 - job:
     name: publish-openstack-octavia-amphora-image-xenial
     parent: publish-openstack-octavia-amphora-image