Merge pull request php-webdriver#260 from black-silence/issue259

fix issue php-webdriver#259

Author: gfosco

lib/Firefox/FirefoxProfile.php

@@ -16,6 +16,7 @@
 namespace Facebook\WebDriver\Firefox;
 
 use Facebook\WebDriver\Exception\WebDriverException;
+use FilesystemIterator;
 use RecursiveDirectoryIterator;
 use RecursiveIteratorIterator;
 use ZipArchive;
@@ -170,7 +171,7 @@ private function deleteDirectory($directory) {
 
     rmdir($directory);
   }
-  
+
   /**
    * @param string $xpi        The path to the .xpi extension.
    * @param string $target_dir The path to the unzip directory.