Fix a PHP version requirenment in composer file

Author: voronkovich

composer.json

@@ -8,7 +8,7 @@
         "classmap": [ "app/AppKernel.php", "app/AppCache.php" ]
     },
     "require": {
-        "php"                                  : ">=5.3.9",
+        "php"                                  : ">=5.5.9",
         "ext-pdo_sqlite"                       : "*",
         "doctrine/doctrine-bundle"             : "^1.6",
         "doctrine/doctrine-fixtures-bundle"    : "^2.2",