Mitaka: bundle required openstack packages for contrail-cloud/network…

…ing install

In our test environment, we provide the openstack repo packages required
for contrail install by means of cfg-openstack-extra, database-openstack-extra
and vrouter-openstack-extra packages.

Bundle all contrail required openstack packages into the <>-openstack-extra.tgz
that we package.

Change-Id: I045c8442acc184c42580edff0d9c4cb88f030582
Closes-Bug: #1671252, #1657920, #1644483