Refs #6098 - revert to fix build.

Code/Mantid/MantidQt/SliceViewer/src/PhysicalCrossPeak.cpp

@@ -64,7 +64,7 @@ namespace MantidQt
   */
   MantidQt::SliceViewer::CrossPeakPrimitives PhysicalCrossPeak::draw(const double& windowHeight, const double& windowWidth) const
   {
-    CrossPeakPrimitives drawingObjects;
+    CrossPeakPrimitives drawingObjects = {};
     if(isViewable())
     {
       const int halfCrossHeight = int(windowHeight * m_crossViewFraction);

Code/Mantid/MantidQt/SliceViewer/src/PhysicalSphericalPeak.cpp

@@ -84,7 +84,7 @@ namespace MantidQt
       */
       MantidQt::SliceViewer::SphericalPeakPrimitives PhysicalSphericalPeak::draw(const double& windowHeight, const double& windowWidth, const double& viewWidth, const double& viewHeight) const
       {
-        SphericalPeakPrimitives drawingObjects;
+          SphericalPeakPrimitives drawingObjects = {};
         if(this->isViewable())
         {
           // Scale factor for going from viewX to windowX