Add property $_config to StaticConfigTrait.

This avoids having to declare the property in each class that uses the trait.

src/Cache/Cache.php

@@ -76,16 +76,6 @@ class Cache {
  */
 	protected static $_enabled = true;
 
-/**
- * Cache configuration.
- *
- * Keeps the permanent/default settings for each cache engine.
- * These settings are used to reset the engines after temporary modification.
- *
- * @var array
- */
-	protected static $_config = [];
-
 /**
  * Group to Config mapping
  *

src/Core/StaticConfigTrait.php

@@ -1,7 +1,5 @@
 <?php
 /**
- * PHP 5
- *
  * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
  * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
  *
@@ -27,6 +25,13 @@
  */
 trait StaticConfigTrait {
 
+/**
+ * Configuration sets.
+ *
+ * @var array
+ */
+	protected static $_config = [];
+
 /**
  * This method can be used to define confguration adapters for an application
  * or read existing configuration.

src/Datasource/ConnectionManager.php

@@ -33,13 +33,6 @@ class ConnectionManager {
 		config as protected _config;
 	}
 
-/**
- * Holds a list of connection configurations
- *
- * @var array
- */
-	protected static $_config = [];
-
 /**
  * A map of connection aliases.
  *

src/Log/Log.php

@@ -115,13 +115,6 @@ class Log {
  */
 	protected static $_dirtyConfig = false;
 
-/**
- * An array of configured loggers.
- *
- * @var array
- */
-	protected static $_config = [];
-
 /**
  * LogEngineRegistry class
  *

src/Network/Email/Email.php

@@ -295,13 +295,6 @@ class Email {
  */
 	protected $_boundary = null;
 
-/**
- * Configuration profiles for use in instances.
- *
- * @var array
- */
-	protected static $_config = [];
-
 /**
  * Configuration profiles for transports.
  *