add socket validation

src/Xash3D/Master.php

@@ -19,10 +19,13 @@ class Master
             $port
         );
 
-        stream_set_timeout(
+        if ($this->_socket)
-            $this->_socket,
+        {
-            $timeout
+            stream_set_timeout(
-        );
+                $this->_socket,
+                $timeout
+            );
+        }
     }
 
     public function __destruct()