conpaas-core: set private_ip to IPOP IP address to avoid IP rewriting on EC2


git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@4920 ef35cc4a-2640-4bbf-98bc-65920db7d8ae
conpaas-core: new_instances should always return a list


git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@4921 ef35cc4a-2640-4bbf-98bc-65920db7d8ae