correct input params in get_samples
correct input params in get_samples

Pollsters must implement get_samples(self, manager, cache, resources),
not get_samples(self, manager, context)

Closes-Bug: #1619575
Change-Id: I0a84355b8c217681ed0cba4bcdaac8433141a2d5

ityaptin/ceilometer,openstack/ceilometer,openstack/ceilometer,ityaptin/ceilometer