fix tests
fix requirement
Fix requirement

- Changed version for python-ceilometerclient in setup.py
- Fixed get_prices_from_costs in case when there is no total_usage
- Fix flake8
Merge branch 'feature/fix-tests' of https://github.com/kula1922/ralph_pricing into feature/fix-tests
Fix tests and cailometer plugin version

- Changed cailometerclient version from ==1.0.8 to >=1.0.9 in setup.py
- Fix bug in report utils when total_usage and cost.cost is == 0
- Fix flake8
Update travis configuration

- Manually install ralph and ralph pricing in travis
- Change pip install for pip 1.5.4
Fix problem with migrations

- Remove creating unique keys in first migration
- Remove creating unique kyes in 14th migrations
- Update queriest in 20th migration
Merge pull request #107 from kula1922/feature/fix-tests

Feature/fix tests
Merge branch 'release/2.1.0' of https://github.com/allegro/ralph_pricing into release/2.1.0