Fix minimum Pandas required version
Fix minimum Pandas required version

We need pandas 0.17.0 to use sort_values()

Change-Id: I47bcbce4a725ff669eaed01350aa611928918ebd

gnocchixyz/gnocchi,sileht/gnocchi,leandroreox/gnocchi,gnocchixyz/gnocchi,sileht/gnocchi,leandroreox/gnocchi