Removed if-statement for review notes

https://github.com/socketio/socket.io-client-swift/pull/651#pullrequestreview-32616528

Source/SocketEngine.swift

@@ -244,10 +244,7 @@ public final class SocketEngine : NSObject, URLSessionDelegate, SocketEnginePoll
 
     private func createWebsocketAndConnect() {
         
-        if let oldWs = ws {
-            oldWs.delegate = nil
-        }
-        
+        ws?.delegate = nil
         ws = WebSocket(url: urlWebSocketWithSid as URL)
 
         if cookies != nil {

Source/SocketIOClient.swift

@@ -120,10 +120,7 @@ public final class SocketIOClient : NSObject, SocketEngineClient, SocketParsable
     private func addEngine() -> SocketEngineSpec {
         DefaultSocketLogger.Logger.log("Adding engine", type: logType, args: "")
 
-        if let oldEngine = engine {
-            oldEngine.client = nil
-        }
-        
+        engine?.client = nil
         engine = SocketEngine(client: self, url: socketURL, config: config)
 
         return engine!