Remove unused code + Increase frequeuncy of host heartbeat update

ucloud/common/network.py

@@ -70,15 +70,3 @@ def delete_network_interface(iface):
     except Exception:
         logger.exception("Interface %s Deletion failed", iface)
 
-
-def find_free_port():
-    with closing(
-        socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    ) as s:
-        try:
-            s.bind(("", 0))
-            s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        except Exception:
-            return None
-        else:
-            return s.getsockname()[1]