libnm: add small delay for connectivity changed

The primary connection signal from libnm is triggered way too soon,
before the routes added, causing generally the first requests to
failed with some socket error. Delaying this a bit helps the first
requests to pass successfully.

Change-Id: I09551ff748ac503dde187c0c937b9405cd33a914

src/app/mainapplication.cpp

@@ -35,6 +35,7 @@
 #include <QMenu>
 #include <QQmlContext>
 #include <QResource>
+#include <QTimer>
 #include <QTranslator>
 #include <QLibraryInfo>
 #include <QQuickWindow>
@@ -165,7 +166,7 @@ MainApplication::init()
 #endif
 
     connect(connectivityMonitor_.get(), &ConnectivityMonitor::connectivityChanged, [this] {
-        lrcInstance_->connectivityChanged();
+        QTimer::singleShot(500, this, [&]() { lrcInstance_->connectivityChanged(); });
     });
 
     connect(this, &QGuiApplication::focusWindowChanged, [this] {