Tried fixing rollback and concurrent update. Not upto mark.
Rollback fix and code cleanup
Code clean up.

Removed import causing heat-engine service start up failure.
Removing not needed code to make code base slim.
Config files to run PoC on devstack with minimal services.
Adding dummy resource and fixing update-replace.
Some minor fixes for stack failure.
Moving to centralized DB operations.
Merge branch 'exp-anant' of https://github.com/anantpatil/heat-convergence-poc into exp-anant