Saving an expired value should be the same as removing that value (#49)

* Saving an expired value should be the same as removing that value

* Updated tests version

Author: Nyholm

composer.json

@@ -28,7 +28,7 @@
     },
     "require-dev": {
         "phpunit/phpunit":         "^4.1|^5.1",
-        "cache/integration-tests": "^0.9",
+        "cache/integration-tests": "^0.10",
         "symfony/cache":           "dev-master"
     },
     "autoload":    {