Fix unused parameter warning.

Libs/XNAT/Core/ctkXnatResource.cpp

@@ -82,7 +82,7 @@ void ctkXnatResource::fetchImpl()
 }
 
 //----------------------------------------------------------------------------
-void ctkXnatResource::download(const QString& filename)
+void ctkXnatResource::download(const QString& /*filename*/)
 {
 //  this->session()->download(this, filename);
 }