0021308: Remove hard-coded dependency of the external mesh plugins from the SMESH...

0021308: Remove hard-coded dependency of the external mesh plugins from the SMESH module

 void SMESH_Mesh_i::SetParameters(const char* theParameters)
 {
-  SMESH_Gen_i::GetSMESHGen()->UpdateParameters(SMESH::SMESH_Mesh::_narrow(_this()),
-                                               CORBA::string_dup(theParameters));
+  SMESH_Gen_i::GetSMESHGen()->UpdateParameters(theParameters);