fix bug in MElement::getVolume (uninitialized variable!)

Geo/MElement.cpp

@@ -146,11 +146,12 @@ SPoint3 MElement::barycenter()
   return p;
 }
 
-double MElement::getVolume(){
+double MElement::getVolume()
+{
   int npts;
   IntPt *pts;
   getIntegrationPoints(getDim() * (getPolynomialOrder() - 1), &npts, &pts);
-  double vol;
+  double vol = 0.;
   for (int i = 0; i < npts; i++){
     vol += getJacobianDeterminant(pts[i].pt[0], pts[i].pt[1], pts[i].pt[2])
       * pts[i].weight;    
@@ -158,7 +159,6 @@ double MElement::getVolume(){
   return vol;
 }
 
-
 int MElement::getVolumeSign()
 {
   double v = getVolume();