[FIX] don't trigger blockUI before displaying potential alerts

bzr revid: xmo@openerp.com-20120110133020-etejse7odvr8ancj

diff --cc addons/web/static/src/js/data_export.js
index 78dc3be,ab7ea5e..c6fe964
--- 1/addons/web/static/src/js/data_export.js
--- 2/addons/web/static/src/js/data_export.js
+++ b/addons/web/static/src/js/data_export.js
@@@ -349,7 -349,7 +349,7 @@@ openerp.web.DataExport = openerp.web.Di
              export_field.push($(this).val());
          });
          if (!export_field.length) {
-             alert('Please select fields to save export list...');
 -            alert(_t('Please select fields to save export list...'));
++            alert(_t("Please select fields to save export list..."));
          }
          return export_field;
      },
@@@ -361,7 -360,7 +360,7 @@@
              exported_fields.push({name: fieldname, label: $(this).text()});
          });
          if (_.isEmpty(exported_fields)) {
-             alert('Please select fields to export...');
 -            alert(_t('Please select fields to export...'));
++            alert(_t("Please select fields to export..."));
              return;
          }