Fixes attempt to concat boolean value

Fixes #5722

scripts/lua/modules/alert_utils.lua

@@ -570,6 +570,9 @@ function alert_utils.getLinkToPastFlows(ifid, alert, alert_json)
 	    past_flows_filter["epoch_end"] = past_flows_filter["epoch_begin"] + duration
 	 end
 
+	 -- TODO: Temporarily disabled, WIP
+	 past_flows_filter = {}
+
 	 -- Return the link augmented with the filter
 	 return string.format("%s/lua/pro/nindex_query.lua?", ntop.getHttpPrefix(), table.tconcat(past_flows_filter, "=", "&"))
       end