Do not install nova-cert for older releases than Mitaka

Nova cert is needed only for EC2 api, which was removed from
Nova in Mitaka. This patch makes sure we do not install
nova-cert by default for newer openstack versions than Mitaka.

Change-Id: I1da48224d427917dfd2f2afe94d1e547c681f825
Related-Prod: PROD-19158
1 file changed