use _derive_router_hostnames for list of hostnames

inventory_provider/tasks/worker.py

@@ -144,14 +144,8 @@ def update_equipment_locations():
     for k in r.scan_iter('opsdb:location:*'):
         r.delete(k)
 
-    hostnames = []
-    for k in r.keys('netconf:*'):
-        m = re.match('^netconf:(.+)$', k.decode('utf-8'))
-        assert m
-        hostnames.append(m.group(1))
-
     with db.connection(InventoryTask.config["ops-db"]) as cx:
-        for h in hostnames:
+        for h in _derive_router_hostnames(InventoryTask.config):
             for ld in opsdb.lookup_pop_info(cx, h):
                 r.set('opsdb:location:%s' % h, json.dumps(ld))