Use get_secret instead of secret

The new get_secret method allows the 'secrets' databag to be renamed,
just like all other databags.

Change-Id: Ic8be5d19a112d78e22716c0cd571efc7186ac9ce
Related-Bug: #1288784
Add hypervisor_inspector in ceilometer.conf

Add hypervisor_inspector configuration in ceilometer.conf, it's necessary
in some cases, for example, if we want to use this cookbook's template to
support installation of ceilometer agent on windows platform.

Change-Id: Ie42eb3d055ff1dbc3944adb18777073044983ed4
Closes-Bug: #1300080
Merge "Add hypervisor_inspector in ceilometer.conf"