It was found in some installations that python-cachetools needed
to be present on the system. This can happen if the installation
was configured for the Java mon-persister but the recreate-metric-id
tool is written in Python. Added a bullet item to describe this
dependency and the quick workaround of installing the
python-cachetools package.
Change-Id: I25635c069a5ed21342780a28b516c74b61dae30b
Story: 2005305
Task: 30611
c32885aed8