Incremented chefdk to 2.3.4
Incremented chefdk to 2.3.4

- incremented chefdk release to 2.3.4
- populated some NODEPOOL_* macros for future use

Implements blueprint modern-chef

Change-Id: I00e2237cef0c9aa35f78d3ccec04a1c7b9271ce8

openstack/cookbook-openstack-common,openstack/cookbook-openstack-common