FIX: Remove hard coded path

Data/Input/radarsat2/radarsat2-1.geom

@@ -40,7 +40,6 @@ platform_position[4]ephemeris.position:  (-211215.549626422,-4807103.54584084,53
 platform_position[4]ephemeris.velocity:  (-2242.74289199728,-5301.198083286,-4877.50945094166)
 platform_positions_count:  5
 product_georeferenced_flag:  false
-product_xml_filename:  /home/julien/Projects/orfeo-toolbox/misc/OTB-LargeInput/RADARSAT2/ALTONA/Fine_Quad-Pol_Dataset/PK6621_DK406_FQ9_20080405_124900_HH_VV_HV_VH_SLC_Altona/product.xml
 rect:  0 0 2821 12952
 ref_point.col:  0
 ref_point.distance:  890636.095102868

Modules/Core/Metadata/src/otbRadarsat2ImageMetadataInterface.cxx

@@ -30,6 +30,7 @@
 // useful constants
 #include <otbMath.h>
 #include "otbXMLMetadataSupplier.h"
+#include <boost/filesystem.hpp> 
 
 namespace otb
 {
@@ -305,10 +306,10 @@ void Radarsat2ImageMetadataInterface::ParseGeom(const MetadataSupplierInterface
   m_Imd.Add(MDStr::SensorID, "SAR");  
 
   // Product file
-  std::string ProductFilePath = mds.GetAs<std::string>("", "product_xml_filename");
+  auto ProductFilePath = boost::filesystem::path(mds.GetResourceFile());
   if (!ProductFilePath.empty())
   {
-    XMLMetadataSupplier ProductMS(ProductFilePath);
+    XMLMetadataSupplier ProductMS((ProductFilePath.remove_filename() /= "product.xml").string());
     m_Imd.Add(MDStr::Mission, ProductMS.GetAs<std::string>("product.sourceAttributes.satellite"));
     m_Imd.Add(MDNum::NumberOfLines, ProductMS.GetAs<int>("product.imageAttributes.rasterAttributes.numberOfLines"));
     m_Imd.Add(MDNum::NumberOfColumns, ProductMS.GetAs<int>("product.imageAttributes.rasterAttributes.numberOfSamplesPerLine"));