[libgda] Revert "GdaDataModel: fix memory leak at import from model"

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit f0d7d703eb71c71ddedf2251ba831dbee2e664f2
Author: Daniel Espinosa <esodan gmail com>
Date:   Mon Apr 22 13:41:57 2019 -0500

    Revert "GdaDataModel: fix memory leak at import from model"
    
    This reverts commit dabdf35ccdb91baa29754382888a5406d4e22dce.

 libgda/gda-data-model.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)
---
diff --git a/libgda/gda-data-model.c b/libgda/gda-data-model.c
index 56d950e0d..c454be53b 100644
--- a/libgda/gda-data-model.c
+++ b/libgda/gda-data-model.c
@@ -1984,7 +1984,6 @@ gda_data_model_import_from_model (GdaDataModel *to, GdaDataModel *from,
                        g_set_error (error, GDA_DATA_MODEL_ERROR, GDA_DATA_MODEL_VALUE_TYPE_ERROR,
                                     _("Destination column %d can't be NULL but has no correspondence in the "
                                       "source data model"), i);
-      g_object_unref (from_iter);
                        return FALSE;
                }
                if (param) {
@@ -1998,7 +1997,6 @@ gda_data_model_import_from_model (GdaDataModel *to, GdaDataModel *from,
                                             gda_g_type_to_string (gda_column_get_g_type (column)),
                                             col,
                                             gda_g_type_to_string (gda_holder_get_g_type (param)));
-        g_object_unref (from_iter);
                                return FALSE;
                        }
                }
@@ -2136,12 +2134,17 @@ gda_data_model_import_from_model (GdaDataModel *to, GdaDataModel *from,
        }
        
        /* free memory */
-  g_list_free_full (append_values, (GDestroyNotify) gda_value_free);
-       g_free (append_types);
-  g_object_unref (from_iter);
-  if (copy_params) {
-    g_slist_free (copy_params);
-  }
+       {
+               GList *vlist;
+
+               vlist = append_values;
+               while (vlist) {
+                       if (vlist->data)
+                               gda_value_free ((GValue *) vlist->data);
+                       vlist = g_list_next (vlist);
+               }
+               g_free (append_types);
+       }
 
        if (retval && (to_row >= 0)) {
                /* remove extra rows */