wifi: bypass available check for hidden APs during activation (rh #1069844)
Because not all clients set the 'hidden' property in a connection for hidden/non-SSID-broadcasting networks, they may not show up in the device's available-connections property. After the PendingActivation object removal, all activations require the connection to be in available-connections, and thus hidden SSID networks could not be activated. Unfortunately check_connection_available() is used both during activation and to populate the available-connections array, but we only want to special-case activation paths, and still ensure that SSIDs not found in the scan list are not in available-connections. To make it clear this is a WiFi only hack, and that we should remove it at some point in the future, create another class method specifically for hidden WiFi and use that in activation paths to special-case hidden WiFi connection activation.