quick fix of mistyped symfony 2.8

Author: saimaz

composer.json

@@ -20,8 +20,7 @@
         "doctrine/cache": "~1.4",
         "doctrine/collections": "~1.4",
         "monolog/monolog": "~1.10",
-        "ongr/elasticsearch-dsl": "~5.0",
-        "symfony/symfony": "~2.8"
+        "ongr/elasticsearch-dsl": "~5.0"
     },
     "require-dev": {
         "mikey179/vfsStream": "~1.4",