adapt to lrc api changes

Linked to change 3003

Change-Id: Ib779a04021fdd6ede2dcd99141d7671d34c5c9e1
Tuleap: #44
diff --git a/videowidget.cpp b/videowidget.cpp
index 7c45e55..9079a92 100644
--- a/videowidget.cpp
+++ b/videowidget.cpp
@@ -23,10 +23,10 @@
   , previewRenderer_(nullptr)
   , renderer_(nullptr)
 {
-    connect(Video::PreviewManager::instance(),
+    connect(&Video::PreviewManager::instance(),
             SIGNAL(previewStarted(Video::Renderer*)),
             this, SLOT(previewStarted(Video::Renderer*)));
-    connect(CallModel::instance(),
+    connect(&CallModel::instance(),
             SIGNAL(rendererAdded(Call*,Video::Renderer*)),
             this, SLOT(callInitiated(Call*, Video::Renderer*)),
             Qt::ConnectionType::DirectConnection);