Add eraseCredentials option to WiFi disconnect method.

libraries/ESP8266WiFi/src/ESP8266WiFiSTA.cpp

@@ -357,11 +357,28 @@ bool ESP8266WiFiSTAClass::reconnect() {
  * @param wifioff
  * @return  one value of wl_status_t enum
  */
-bool ESP8266WiFiSTAClass::disconnect(bool wifioff) {
+bool ESP8266WiFiSTAClass::disconnect(bool wifioff, bool eraseap) {
+{
+    return disconnect(wifioff, false);
+}
+
+/**
+ * Disconnect from the network
+ * @param wifioff
+ * @param eraseap
+ * @return  one value of wl_status_t enum
+ */
+bool ESP8266WiFiSTAClass::disconnect(bool wifioff, bool eraseap) {
     bool ret = false;
+
+    // Read current config.
     struct station_config conf;
-    *conf.ssid = 0;
-    *conf.password = 0;
+    wifi_station_get_config(&conf);
+
+    if (eraseap) {
+        memset(&conf.ssid, 0, sizeof(conf.ssid));
+        memset(&conf.password, 0, sizeof(conf.password));
+    };
 
     // API Reference: wifi_station_disconnect() need to be called after system initializes and the ESP8266 Station mode is enabled.
     if (WiFi.getMode() & WIFI_STA)

libraries/ESP8266WiFi/src/ESP8266WiFiSTA.h

@@ -48,7 +48,9 @@ class ESP8266WiFiSTAClass: public LwipIntf {
         bool config(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dns1 = (uint32_t)0x00000000, IPAddress dns2 = (uint32_t)0x00000000);
 
         bool reconnect();
+
         bool disconnect(bool wifioff = false);
+        bool disconnect(bool wifioff = false, bool eraseap = false);
 
         bool isConnected();