sample name does NOT match registered stevedore hardware pollster plugin name

The sample names generated hardware pollsters don't match the registered stevedore extension name, which would result the ceilometer.pipeline.Source.support_meter fail to give the right result, so that the corresponding sample can never be published.

e.g.

sample name from the pollster ceilometer.hardware.pollsters.disk.DiskTotalPollster is "disk.size.total", which does not match its registered stevedore extension name "hardware.disk.size.total" which would be used in the pipeline source definition.

sources:
    - name: "snmp.disk"
      interval: 600
      meters:
          - "hardware.disk.size.total"
          - "hardware.network.incoming.bytes"
      resources:
          - "snmp://127.0.0.1"
      sinks:
          - 'disk.sink'