Fix up PHPStan errors.

phpstan.neon

@@ -4,6 +4,8 @@ parameters:
     ignoreErrors:
         - '#Function wincache_ucache_[a-zA-Z0-9_]+ not found#'
         - '#Function xcache_[a-zA-Z0-9_]+ not found#'
+        - '#Function mcrypt_[a-zA-Z0-9_]+ not found#'
+        - '#Function apcu_[a-zA-Z0-9_]+ not found#'
         - '#Function fastcgi_[a-zA-Z0-9_]+ not found#'
         - '#Cake\\Database\\Type\\[a-zA-Z0-9_]+Type::__construct\(\) does not call parent constructor from Cake\\Database\\Type#'
         - '#Constructor of class Cake\\[a-zA-Z0-9_\\]+ has an unused parameter#'
@@ -16,6 +18,9 @@ parameters:
         - '#Access to an undefined property Cake\\[a-zA-Z0-9_\\]+::\$_validViewOptions#'
         - '#Access to an undefined property Cake\\Database\\Driver::\$_connection#'
         - '#Constant XC_TYPE_VAR not found#'
+        - '#Instantiated class APCUIterator not found#'
+        - '#Constant APC_[A-Z0-9_]+ not found#'
+        - '#Constant MCRYPT_[A-Z0-9_]+ not found#'
         - '#Call to static method id\(\) on an unknown class PHPUnit_Runner_Version#'
     earlyTerminatingMethodCalls:
         Cake\Shell\Shell:

src/Cache/Engine/ApcEngine.php

@@ -230,6 +230,7 @@ public function groups()
      */
     public function clearGroup($group)
     {
+        $success = false;
         apcu_inc($this->_config['prefix'] . $group, 1, $success);
 
         return $success;

src/Console/CommandCollection.php

@@ -116,7 +116,7 @@ public function has($name)
      * Get the target for a command.
      *
      * @param string $name The named shell.
-     * @return string|Cake\Console\Shell Either the shell class or an instance.
+     * @return string|\Cake\Console\Shell Either the shell class or an instance.
      * @throws \InvalidArgumentException when unknown commands are fetched.
      */
     public function get($name)