- Add mappings between counter type in collectd and Ceilometer.
Previously, all counters were given "gauge" type.
Now, the following mappings are applied:
- gauge -> gauge
- derive -> delta
- absolute, counter -> cumulative
- Add unit tests
Closes-Bug: #1583301
Change-Id: I13e75fcc57ed2b44c2b9a02ee9562f70748d01c2