The change modifies the nova template tasks such that it's now
using the config_template action plugin. This change will make so that
config files can be dynamically updated, by a deployer, at run time,
without requiring the need to modify the in tree templates or defaults.
Partially implements: blueprint tunable-openstack-configuration
Change-Id: I9842ed3fcb2cc4aa379a582359b1ca5d0747f714
a1bc60d4c9