Coverity fixes

151677
151789  - OK as is
152005
152508
154871  - false positive
156593
163235

src/Mod/TechDraw/Gui/QGIHighlight.cpp

@@ -41,6 +41,7 @@ using namespace TechDrawGui;
 
 QGIHighlight::QGIHighlight()
 {
+    m_refText = "";
     m_refSize = 0.0;
     m_circle = new QGraphicsEllipseItem();
     addToGroup(m_circle);