Dell Networking N1100 - No/wrong CPU/memory readings

Discovery: https://p.libren.ms/view/6c2ae37a
Poller: https://p.libren.ms/view/14b37cbf
SNMP: https://github.com/librenms/librenms/files/2044061/powerconnect-hbg-sw02.snmpwalk.txt
MIB: https://github.com/librenms/librenms/files/2044057/Release.6.4.2.6-mibs.zip

Pic 1: https://user-images.githubusercontent.com/23332970/40602189-2e1bccec-6247-11e8-9ba6-04c75d914e72.PNG
Pic2: https://user-images.githubusercontent.com/23332970/40602296-9609c2aa-6247-11e8-97af-d4099fc8c387.PNG

Memory usage is at 37% for all N1100 devices, we are currently monitoring 40 of them. I suspect that librenms is using the wrong OID.

(Imported from https://github.com/librenms/librenms/issues/8778, Original request by: @sirHulda)