Ensure logger assigned before initialising objects

If the logger isn't assigned in the SimpleClient's constructor before the
object graph is initialised, dependencies will get a NullLogger rather than
the LoggerInterface passed in.

Author: ajbonner

pkg/simple-client/SimpleClient.php

@@ -126,9 +126,9 @@ public function __construct($config, LoggerInterface $logger = null)
             ];
         }
 
-        $this->build(['enqueue' => $config]);
-
         $this->logger = $logger ?: new NullLogger();
+
+        $this->build(['enqueue' => $config]);
     }
 
     /**