Don't list raw containments in panels menu

Summary:
Empty panel is now shipped as a LayoutTempate rendering this code
redundant.

Test Plan: Still have both default and empty panels listed

Reviewers: #plasma

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D2747

shell/shellcorona.cpp

@@ -1631,14 +1631,7 @@ void ShellCorona::populateAddPanelsMenu()
     m_addPanelsMenu->clear();
     const KPluginInfo emptyInfo;
 
-    KPluginInfo::List panelContainmentPlugins = Plasma::PluginLoader::listContainmentsOfType(QStringLiteral("Panel"));
     QMap<QString, QPair<KPluginInfo, KPluginMetaData> > sorted;
-    foreach (const KPluginInfo &plugin, panelContainmentPlugins) {
-        if (plugin.property(QStringLiteral("NoDisplay")).toString() == QStringLiteral("true")) {
-            continue;
-        }
-        sorted.insert(plugin.name(), qMakePair(plugin, KPluginMetaData()));
-    }
 
     auto filter = [](const KPluginMetaData &md) -> bool
     {