Merge branch '3.3' into 3.4

* 3.3:
  [VarDumper] Fix tests with phpredis 3.1.3
  [DI] Fix reading env vars from fastcgi params
  Allow phpdocumentor/reflection-docblock 4.
  [VarDumper] play nice with open_basedir when looking for composer.json

Author: nicolas-grekas

composer.json

@@ -28,7 +28,7 @@
         "doctrine/annotations": "~1.0",
         "symfony/dependency-injection": "~3.2|~4.0",
         "doctrine/cache": "~1.0",
-        "phpdocumentor/reflection-docblock": "~3.0"
+        "phpdocumentor/reflection-docblock": "^3.0|^4.0"
     },
     "conflict": {
         "symfony/dependency-injection": "<3.2",