Merge branch '3.1'

* 3.1:
  added a comment about a workaround
  [Finder] no PHP warning on empty directory iteration
  [HttpKernel] Fixed the nullable support for php 7.1 and below
  fixed CS
  [Form] Fix typo in doc comment
  Fix version constraint
  [Config] Handle open_basedir restrictions in FileLocator
  Fixed bad merge
  [DoctrineBridge][PropertyInfo] Treat Doctrine decimal type as string
  [bugfix] [Console] Set `Input::$interactive` to `false` when command is executed with `--quiet` as verbosity level
  Use JSON_UNESCAPED_SLASHES for lint commands output
  Fixed collapsed ChoiceType options attributes
  [FrameworkBundle] Remove cache clearer default value in config
  Consider the umask setting when dumping a file.
  Fixed the nullable support for php 7.1 and below
  Make ReflectionExtractor compatible with ReflectionType changes in PHP 7.1

Author: fabpot

FileLocator.php

@@ -59,7 +59,7 @@ public function locate($name, $currentPath = null, $first = true)
         $filepaths = array();
 
         foreach ($paths as $path) {
-            if (file_exists($file = $path.DIRECTORY_SEPARATOR.$name)) {
+            if (@file_exists($file = $path.DIRECTORY_SEPARATOR.$name)) {
                 if (true === $first) {
                     return $file;
                 }