Description of problem:
OSP 10 moved metrics-related API calls to Gnocchi. We need update Openstack provider with a new service for metrics called Gnocchi (different to metering for Ceilometer) and use it for metrics loading from Overcloud.

Undercloud should use an existing Ceilometer API calls in OSP10 and older (and in close future until Gnocchi appears in overcloud - 11/Ocata or later).

Version-Release number of selected component (if applicable):
5.7, 5.6

How reproducible:
always with OSP10 overcloud

Steps to Reproduce:
1. setup OSP10
2. add Cloud provider
3. provision an instance
4. capture metrics from rails console - Vm.last.perf_capture("realtime", 3.hours.ago.utc, Time.now.utc)

Actual results:
getting 410 error for /v2/meters: This telemetry installation is configured to use Gnocchi. Please use the Gnocchi API available on the metric endpoint to retrieve data.

Expected results:
no errors, metrics were loaded

Additional info:
Error log: http://paste.openstack.org/show/586570/