Merge branch '3.1'

* 3.1:
  Relax 1 test failing with latest PHP versions
  bumped Symfony version to 2.8.10
  [Cache] Minor cleanup
  Remove usage of __CLASS__ outside of a class
  [HttpKernel] Fix variable conflicting name
  [Process] Fix double-fread() when reading unix pipes
  [Process] Fix AbstractPipes::write() for a situation seen on HHVM (at least)
  [Validator] Fix dockblock typehint in XmlFileLoader
  bumped Symfony version to 3.1.4
  updated VERSION for 3.1.3
  updated CHANGELOG for 3.1.3
  bumped Symfony version to 2.8.10
  updated VERSION for 2.8.9
  updated CHANGELOG for 2.8.9
  bumped Symfony version to 2.7.17
  updated VERSION for 2.7.16
  update CONTRIBUTORS for 2.7.16
  updated CHANGELOG for 2.7.16

Conflicts:
	src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
	src/Symfony/Component/HttpKernel/Kernel.php

Author: nicolas-grekas

Kernel.php

@@ -440,8 +440,8 @@ protected function initializeBundles()
                 $hierarchy[] = $name;
             }
 
-            foreach ($hierarchy as $bundle) {
-                $this->bundleMap[$bundle] = $bundleMap;
+            foreach ($hierarchy as $hierarchyBundle) {
+                $this->bundleMap[$hierarchyBundle] = $bundleMap;
                 array_pop($bundleMap);
             }
         }