Support user variables for all OpenStack string config options

builder/openstack/run_config.go

@@ -72,6 +72,9 @@ func (c *RunConfig) Prepare(t *packer.ConfigTemplate) []error {
 		"ssh_timeout":        &c.RawSSHTimeout,
 		"ssh_username":       &c.SSHUsername,
 		"source_image":       &c.SourceImage,
+		"openstack_provider": &c.OpenstackProvider,
+		"floating_ip_pool":   &c.FloatingIpPool,
+		"floating_ip":        &c.FloatingIp,
 	}
 
 	for n, ptr := range templates {