Add support for MDB database information to openldap input (influxdata#6993)

Author: quanah

plugins/inputs/openldap/openldap.go

@@ -56,6 +56,12 @@ var attrTranslate = map[string]string{
 	"monitoredInfo":      "",
 	"monitorOpInitiated": "_initiated",
 	"monitorOpCompleted": "_completed",
+	"olmMDBPagesMax":     "_mdb_pages_max",
+	"olmMDBPagesUsed":    "_mdb_pages_used",
+	"olmMDBPagesFree":    "_mdb_pages_free",
+	"olmMDBReadersMax":   "_mdb_readers_max",
+	"olmMDBReadersUsed":  "_mdb_readers_used",
+	"olmMDBEntries":      "_mdb_entries",
 }
 
 func (o *Openldap) SampleConfig() string {