COMP: Fixing coverity issue 1350187 (uninitialized class members) and moving...

COMP: Fixing coverity issue 1350187 (uninitialized class members) and moving constructor and destructor bodies to cxx file

Modules/Learning/Sampling/include/otbPolygonClassStatisticsAccumulator.h

@@ -62,9 +62,10 @@ public:
 
 protected:
   /** Constructor */
-  PolygonClassStatisticsAccumulator() {}
+  PolygonClassStatisticsAccumulator();
+    
   /** Destructor */
-  virtual ~PolygonClassStatisticsAccumulator() {}
+  virtual ~PolygonClassStatisticsAccumulator();
 
 private:
   //Number of pixels in all the polygons

Modules/Learning/Sampling/src/otbPolygonClassStatisticsAccumulator.cxx

@@ -21,6 +21,15 @@
 namespace otb
 {
 
+PolygonClassStatisticsAccumulator::PolygonClassStatisticsAccumulator() :
+  m_NbPixelsGlobal(0UL),
+  m_ElmtsInClass(),
+  m_Polygon()
+{}
+  
+PolygonClassStatisticsAccumulator::~PolygonClassStatisticsAccumulator()
+{}
+
 void
 PolygonClassStatisticsAccumulator
 ::Reset()