Remove unnecessary $this.

Related to b3b5e36d42.

extensions/mutex/yii/mutex/Mutex.php

@@ -35,7 +35,7 @@ abstract class Mutex extends Component
 	{
 		if ($this->autoRelease) {
 			$locks = &$this->_locks;
-			register_shutdown_function(function () use ($this, &$locks) {
+			register_shutdown_function(function () use (&$locks) {
 				foreach ($locks as $lock) {
 					$this->release($lock);
 				}

framework/yii/grid/ActionColumn.php

@@ -88,7 +88,7 @@ class ActionColumn extends Column
 	 */
 	protected function renderDataCellContent($model, $index)
 	{
-		return preg_replace_callback('/\\{(\w+)\\}/', function ($matches) use ($this, $model) {
+		return preg_replace_callback('/\\{(\w+)\\}/', function ($matches) use ($model) {
 			$name = $matches[1];
 			if (isset($this->buttons[$name])) {
 				return call_user_func($this->buttons[$name], $model, $this);