Adds genisoimage package dependency to nova-compute

- This change enables the nova-compute agent to generate
  config drives to attach the an instance.
- This allows the config drive to be used to pass
  cloud-init config files to a guest enableing first boot
  configuration.

Change-Id: Id17741b3fce1382350914c1b6c818b0020fe839a
Closes-Bug: #1538288

docker/nova/nova-compute/Dockerfile.j2

@@ -9,6 +9,7 @@ RUN yum -y install \
         openvswitch \
         sysfsutils \
         ceph-common \
+        genisoimage \
     && yum clean all
 
     {% elif base_distro in ['ubuntu'] %}
@@ -21,6 +22,7 @@ RUN apt-get install -y --no-install-recommends \
         ceph-common \
         ironic-common \
         python-ironicclient \
+        genisoimage \
     && apt-get clean \
     && rm -f /etc/nova/nova-compute.conf
 
@@ -34,6 +36,7 @@ RUN yum -y install \
         qemu-img \
         sysfsutils \
         ceph-common \
+        genisoimage \
     && yum clean all
 
     {% elif base_distro in ['ubuntu', 'debian'] %}
@@ -42,6 +45,7 @@ RUN apt-get install -y --no-install-recommends \
         libvirt-dev \
         qemu-utils \
         ceph-common \
+        genisoimage \
     && apt-get clean \
     && mkdir -p /etc/ceph