Install iputils package in neutron containers

This package provides e.g. arping tool which is used by Neutron
services.
On e.g. RHEL7 it was probably installed as some dependency to other
package but on RHEL8 it's missing which cause some errors e.g.
in neutron_l3_agent container.

Change-Id: I9c087164f32cb8a69d2155bc68b6f62233ad58c6
Related-Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1713321

docker/neutron/neutron-base/Dockerfile.j2

@@ -15,6 +15,7 @@ LABEL maintainer="{{ maintainer }}" name="{{ image_name }}" build-date="{{ build
     {% if base_package_type == 'rpm' %}
 
         {% set neutron_base_packages = [
+            'iputils',
             'keepalived',
             'net-tools',
             'radvd',
@@ -90,6 +91,7 @@ RUN mkdir -p /usr/share/neutron \
             'dnsmasq-utils',
             'haproxy',
             'ipset',
+            'iputils',
             'keepalived',
             'net-tools',
             'openvswitch',