Fix Unit of Monasca document
Fix Unit of Monasca document

Semantics descriptions for the metrics in the "System Checks" is fixed.

Change-Id: Iba0c83c552d491bae7c2ca554ac5d8ce9462c39d
Closes-Bug: #1496275

sapcc/monasca-agent,sapcc/monasca-agent,sapcc/monasca-agent