Don't convert input parameters to internal type needlessly.

Calling convert_from_base() for the input ("use") parameters was unnecessary
and potentially confusing to the client code. Simply don't do this, just as we
don't call convert_to_base() for the output ("into") parameters.

Signed-off-by: Vadim Zeitlin <vz-soci@zeitlins.org>

src/core/use-type.cpp

@@ -39,7 +39,9 @@ void standard_use_type::pre_use()
 void standard_use_type::post_use(bool gotData)
 {
     backEnd_->post_use(gotData, ind_);
-    convert_from_base();
+
+    // There is no need to call convert_from_base() here, the converted value
+    // wouldn't be used anyhow.
 }
 
 void standard_use_type::clean_up()