MDL-30480 fix BC regression from MDL-29033

Improve insert_record() and update_record() handling of $dataobject parameter. Some developers expect they can use any class instance there. This is not officially supported, but in any case we should not break backwards compatibility so late in STABLE branch.

Credit for discovery goes to Pascal Maury, thanks!

lib/dmllib.php

@@ -1448,6 +1448,14 @@ function insert_record($table, $dataobject, $returnid=true, $primarykey='id') {
     if (is_array($dataobject)) {
         debugging('Warning. Wrong call to insert_record(). $dataobject must be an object. array found instead', DEBUG_DEVELOPER);
         $dataobject = (object)$dataobject;
+    } else if (is_object($dataobject)) {
+        // make sure there are no properties or private methods because we cast to array later,
+        // at the same time this undos the object references so that PHP 5 works the same as PHP 4,
+        // the main reason for this is BC after the dirty magic hack introduction
+        if ($properties = get_object_vars($dataobject)) {
+            $dataobject = (object)$properties;
+        }
+        unset($properties);
     }
 
 /// Temporary hack as part of phasing out all access to obsolete user tables  XXX
@@ -1643,6 +1651,14 @@ function update_record($table, $dataobject) {
     if (is_array($dataobject)) {
         debugging('Warning. Wrong call to update_record(). $dataobject must be an object. array found instead', DEBUG_DEVELOPER);
         $dataobject = (object)$dataobject;
+    } else if (is_object($dataobject)) {
+        // make sure there are no properties or private methods because we cast to array later,
+        // at the same time this undos the object references so that PHP 5 works the same as PHP 4,
+        // the main reason for this is BC after the dirty magic hack introduction
+        if ($properties = get_object_vars($dataobject)) {
+            $dataobject = (object)$properties;
+        }
+        unset($properties);
     }
 
 /// Extra protection against SQL injections