Better index hints

As X-Road usually has more service clients than producers, using client based index returns fewer rows and performs better

reports_module/opmon_reports/database_manager.py

@@ -215,9 +215,9 @@ def get_faulty_documents(self, target, start_time, end_time):
                     "producer.requestInTs": {"$gte": start_time, "$lte": end_time}
                 },
                 "hint": [
-                    ("client.serviceMemberCode", 1),
-                    ("client.serviceSubsystemCode", 1),
-                    ("client.requestInTs", 1)
+                    ("producer.clientMemberCode", 1),
+                    ("producer.clientSubsystemCode", 1),
+                    ("producer.requestInTs", 1)
                 ]
             }