Index: lib/grade/grade_grade.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- lib/grade/grade_grade.php	(date 1442940843000)
+++ lib/grade/grade_grade.php	(revision )
@@ -352,9 +352,9 @@
 
         // Check to see if the gradebook is frozen. This allows grades to not be altered at all until a user verifies that they
         // wish to update the grades.
-        $gradebookcalculationsfreeze = get_config('core', 'gradebook_calculations_freeze_' . $this->grade_item->courseid);
+        $gradebookcalculationsfreeze = 'gradebook_calculations_freeze_' . $this->grade_item->courseid;
         // Gradebook is frozen, run through old code.
-        if ($gradebookcalculationsfreeze && (int)$gradebookcalculationsfreeze <= 20150627) {
+        if (property_exists($CFG, $gradebookcalculationsfreeze) && (int)$CFG->$gradebookcalculationsfreeze <= 20150627) {
             // Only aggregate items use separate min grades.
             if ($minmaxtouse == GRADE_MIN_MAX_FROM_GRADE_GRADE || $this->grade_item->is_aggregate_item()) {
                 return array($this->rawgrademin, $this->rawgrademax);