QmlDesigner: Load plugins early enough for views

This ensures the plugins are loaded early enough to install views.

Change-Id: Ie2dfaf510a8ab1cd924ed96cdc8efba454ffb29b
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/designercore/metainfo/metainfo.cpp

@@ -187,6 +187,8 @@ void MetaInfo::clearGlobal()
 void MetaInfo::setPluginPaths(const QStringList &paths)
 {
     s_pluginDirs = paths;
+    global();
+    clearGlobal();
 }
 
 bool MetaInfo::isGlobal() const