Change counter to sample vocable in cm.compute

This changes counter to sample vocable in ceilometer.compute code

Parts of the blueprint remove-counter

Change-Id: I69a66935254e2d769ed58c2911819549cbe0f5f0
Change counter to sample vocable in cm.image

This changes counter to sample vocable in ceilometer.image code

Parts of the blueprint remove-counter

Change-Id: Ida25da18642b0b72643841d9221799bb17ebbfdc
Merge "Change counter to sample vocable in cm.compute"
Merge "Change counter to sample vocable in cm.image"