WPS: Add option to disable open networks by default

CONFIG_WPS_REG_DISABLE_OPEN=y can be used to configure wpa_supplicant
to disable open networks by default when wps_reg command is used to
learn the current AP settings. When this is enabled, there will be a
WPS-OPEN-NETWORK ctrl_iface event and the user will need to explicitly
enable the network (e.g., with "select_network <id>") to connect to
the open network.

src/common/wpa_ctrl.h

@@ -85,6 +85,8 @@ extern "C" {
 
 #define WPS_EVENT_ENROLLEE_SEEN "WPS-ENROLLEE-SEEN "
 
+#define WPS_EVENT_OPEN_NETWORK "WPS-OPEN-NETWORK "
+
 /* WPS ER events */
 #define WPS_EVENT_ER_AP_ADD "WPS-ER-AP-ADD "
 #define WPS_EVENT_ER_AP_REMOVE "WPS-ER-AP-REMOVE "