Comment 6 for bug 294190

This looks like the logger line, if that's any help:

2180 nm_info ("(%s): supplicant connection state change: %d -> %d",
2181 nm_device_get_iface (dev), old_state, new_state);

http://bazaar.launchpad.net/~network-manager/network-manager/main.resolvconf/annotate/head%3A/src/nm-device-wifi.c

I don't know where the log level is determined, but there's a switch for it in /src/nm-logging.c