Modify update process for definitions

If a definition cannot be patched, remove and recreate
Added prometheus metrics

Modify caching logic

Merge pull request #12 from monasca/cache-failure

Catch failure to update cache on startup and exit

Add ability for versioning of tpr

Merge pull request #10 from monasca/feature/configurable_version

Allow the version to be configurable

1.0.1: Merge pull request #6 from monasca/use-keystone-project

Switch to gophercloud/gophercloud