Fix Designate worker conditional
Fix Designate worker conditional

It needs to be a separate entry in the map_merge arg list, not
combined with the other hieradata.

Change-Id: I54234fa880d2c86e23bc28ed904b8f372064575b

dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates