Possible fix for RRD updates disappearing
Possible fix for RRD updates disappearing

The last update time is now specific for each SwitchStat instance.

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