ZEN-12650 Interfaces cannot be deleted from /Server/Ssh/Linux devices

  - Check if the device exists on the interface before trying to add/remove attributes to the mac address cache

  Port ZEN-9115 to RM 5.0.0
Merge pull request #261 from zenoss/feature/ZEN-12650

ZEN-12650 Interfaces cannot be deleted from /Server/Ssh/Linux devices