small fix for default_properties

Author: bigfooted

SU2_CFD/src/drivers/CDriver.cpp

@@ -2313,9 +2313,17 @@ void CDriver::InitializeNumerics(CConfig *config, CGeometry **geometry, CSolver
 
       ifstream properties_file;
 
+
       string filename = config->GetFEA_FileName();
+
+      unsigned short lastindex = filename.find_last_of('.');
+      filename = filename.substr(0, lastindex);
+
       if (nZone > 1)
-        filename = config->GetMultizone_FileName(filename, iZone, ".dat");
+        filename = config->GetMultizone_FileName(filename, iZone, "");
+
+      /*--- At the moment we stay consistent with the default extension .dat for all input files. ---*/
+      filename += ".dat";
 
       properties_file.open(filename.data(), ios::in);