station: move scan cancelation to __station_connect_network

An earlier patch fixed a problem where a queued quick scan would
be triggered and fail once already connected, resulting in a state
transition from connected --> autoconnect_full. This fixed the
Connect() path but this could also happen via autoconnect. Starting
from a connected state, the sequence goes:

 - DBus scan is triggered
 - AP disconnects IWD
 - State transition from disconnected --> autoconnect_quick
 - Queue quick scan
 - DBus scan results come in and used to autoconnect
 - A connect work item is inserted ahead of all others, transition
   from autoconnect_quick --> connecting.
 - Connect completes, transition from connecting --> connected
 - Quick scan can finally get triggered, which the kernel fails to
   do since IWD is connected, transition from connected -->
   autoconnect_full.

This can be fixed by checking for a pending quick scan in the
autoconnect path.

src/station.c

@@ -196,6 +196,13 @@ static void station_autoconnect_next(struct station *station)
 
 		if (!r) {
 			station_enter_state(station, STATION_STATE_CONNECTING);
+
+			if (station->quick_scan_id) {
+				scan_cancel(netdev_get_wdev_id(station->netdev),
+						station->quick_scan_id);
+				station->quick_scan_id = 0;
+			}
+
 			return;
 		}
 	}