Make sure the QWebChannel object is initiated in SpeedDial/Restore pages

Make it more robust, this also fixes issue with Qt 5.9

Closes #2329

src/lib/data/html/restore.html

@@ -267,6 +267,11 @@ function addTab(winId, tab)
 
 function init()
 {
+    if (!external.recovery) {
+        setTimeout(init, 50);
+        return;
+    }
+
     var data = external.recovery.restoreData;
     for (var i = 0; i < data.length; ++i) {
         var win = data[i];

src/lib/data/html/speeddial.html

@@ -463,6 +463,11 @@ function disableCentering()
 
 function init()
 {
+    if (!external.speedDial) {
+        setTimeout(init, 50);
+        return;
+    }
+
     %INITIAL-SCRIPT%
 
     external.speedDial.pagesChanged.connect(function() {