avoid generating alert with error message if one oplog node in replicaset got rebooted.
currently if one of the node in appdb/oplogdb goes down for any reasons (for example, linux patch rebooting the node), ops manager generates alert
"Ops Manager was unable to connect to this database and run the
ping command. The database could be down, unreachable, or running with authencation and Ops Manager does not have adequate permissions."
there are still 2 other running nodes in replicaset. so this alert is misleading and generates false alarms.