Pin rabbitmq-server for ubuntu

Ubuntu is also affected by the new rabbitmq server version mismatch
with erlang. Pin it to last known working version until the packaging
mess is fixed.

Change-Id: I5e3ba7762f0990718e4180ffcd3db7722edc17b4
Related-bug: #1814233

docker/rabbitmq/Dockerfile.j2

@@ -29,7 +29,7 @@ LABEL maintainer="{{ maintainer }}" name="{{ image_name }}" build-date="{{ build
          ] %}
     {% else %}
          {% set rabbitmq_packages = rabbitmq_packages + [
-             'rabbitmq-server',
+             'rabbitmq-server=3.7.10-1',
          ] %}
     {% endif %}