[libconnman-qt] Fix crash on connman restart. Contributes to JB#52659

When the service is disconnected clear the currentWifi pointer as the
service it points to will subsequently be deleted leading to a crash if
it is accessed later.

libconnman-qt/networkmanager.cpp

@@ -451,9 +451,16 @@ void NetworkManager::disconnectServices()
     bool wasValid = isValid();
     m_priv->setServicesAvailable(false);
 
+    bool emitDefaultRouteChanged = false;
     if (m_defaultRoute != m_invalidDefaultRoute) {
         m_defaultRoute = m_invalidDefaultRoute;
-        Q_EMIT defaultRouteChanged(m_defaultRoute);
+        emitDefaultRouteChanged = true;
+    }
+
+    bool emitConnectedWifiChanged = false;
+    if (m_priv->m_connectedWifi) {
+        m_priv->m_connectedWifi = NULL;
+        emitConnectedWifiChanged = true;
     }
 
     if (m_proxy) {
@@ -498,6 +505,14 @@ void NetworkManager::disconnectServices()
         Q_EMIT servicesChanged();
     }
 
+    if (emitDefaultRouteChanged) {
+        Q_EMIT defaultRouteChanged(m_defaultRoute);
+    }
+
+    if (emitConnectedWifiChanged) {
+        Q_EMIT connectedWifiChanged();
+    }
+
     if (emitSavedServicesChanged) {
         Q_EMIT savedServicesChanged();
     }