routertools/stattools: Implement default hood as str "Default"

If the default is NULL (as previously), we have ugly problems
with indexing and queries. To circumvent this, the hood is
set to "Default" right at the beginning.

For old data, we add an if to the hood stats calculation.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

ffmap/routertools.py

@@ -91,8 +91,8 @@ def import_nodewatcher_xml(mysql, mac, xml):
 						distance ASC
 					LIMIT 1
 				""",(lat,lng,lat,),"name")
-			else:
-				router_update["hood"] = None
+		if not router_update["hood"]:
+			router_update["hood"] = "Default"
 		
 		if router_id:
 			# statistics

ffmap/stattools.py

@@ -150,6 +150,9 @@ def record_hood_stats(mysql):
 	clients = total_clients_hood(mysql)
 	
 	for hood in clients.keys():
+		if not hood:
+			hood = "Default"
+		
 		old = mysql.findone("SELECT time FROM stats_hood WHERE time = %s AND hood = %s LIMIT 1",(time,hood,))
 		
 		if old: