Fix a few mistakes.

src/Core/Plugin.php

@@ -120,7 +120,7 @@ class Plugin
             return;
         }
 
-        if (!Configure::check('pluginPaths')) {
+        if (!Configure::check('plugins')) {
             try {
                 Configure::load('plugins');
             } catch (\Exception $e) {

tests/TestCase/Core/PluginTest.php

@@ -131,7 +131,6 @@ class PluginTest extends TestCase
         $this->assertEquals(APP . 'src' . DS, Plugin::classPath('TestPlugin'));
     }
 
-
     /**
      * Tests loading multiple plugins at once
      *