Do not install python-nova from repo

We use tarball with source code

Change-Id: If8767fa996bbb4126a4157e51ed4ea52c7b25cec

docker/nova-base/Dockerfile.j2

@@ -2,7 +2,6 @@ FROM {{ namespace }}/openstack-base:{{ tag }}
 MAINTAINER {{ maintainer }}
 
 RUN apt-get install -y --no-install-recommends \
-        python-nova \
         bridge-utils \
         openvswitch-switch \
         iptables \

docker/nova-compute/Dockerfile.j2

@@ -3,6 +3,7 @@ MAINTAINER {{ maintainer }}
 
 RUN apt-get -y install --no-install-recommends \
         libvirt-dev \
+        python-libvirt \
         qemu-utils \
         ceph-common \
         genisoimage \