Working on the implementation of rrdgraph REST endpoint.
Working on the implementation of rrdgraph REST endpoint.

Added an echo when input file cannot be found

netgroup/OSHI-monitoring,netgroup/OSHI-monitoring,ferrarimarco/OSHI-monitoring,ferrarimarco/OSHI-monitoring,StefanoSalsano/OSHI-monitoring,StefanoSalsano/OSHI-monitoring