When regenerate-samples.sh called values like uuid, created_at,
updated_at, provision_state, power_state are updated automatically.
This patch ensures that they restored to original values to minimize
commit diff, as they are not related to change itself.
Add a waiter to wait for node state after update request to make sure
it was applied.
Removed unused anywhere files:
* node-set-power-state.json
* node-states-show-response.json
Change-Id: Iccff575990c9c06b6cc2cb60e93dd962bde46347
e7eb1e63c6