Fix KeystoneWorkers default value
Fix KeystoneWorkers default value

The current default doesn't get expanded to its real value correctly,
the new one should work better, it's according to hiera docs:

https://docs.puppet.com/hiera/3.2/variables.html

Change-Id: I8d1df131d2f1eee4ae0f725358d33a3ecfa3175a

trozet/opnfv-tht,openstack/tripleo-heat-templates,trozet/opnfv-tht,openstack/tripleo-heat-templates,trozet/opnfv-tht,dprince/tripleo-heat-templates,dprince/tripleo-heat-templates