Do not add trailing whitespace to blank lines

lib/Doctrine/ORM/Tools/EntityGenerator.php

@@ -1207,8 +1207,10 @@ public function __construct()
         $lines = explode("\n", $code);
 
         foreach ($lines as $key => $value) {
+            if (!empty($value)) {
                 $lines[$key] = str_repeat($this->spaces, $num) . $lines[$key];
             }
+        }
 
         return implode("\n", $lines);
     }