[Neutron] Ensure ovs agent setup runs for all CONFIG_NEUTRON_ML2_TENANT_NETWORK_TYPES

Previously we used to pick only the first type from tenant network types,
Now packstack parses whole array and sets ovs agent on nodes accordingly.

Change-Id: Ia8c2f4a9a9d932498c893032d90c991625688c8e
Closes-Bug: rhbz#1163697 rhbz#1168242