Revert "Switch getPageSource to use executeScript as discussed on W3C…

… WebDriver mailing list" can be re-reverted with a more complete pageSource script.

This reverts commit 091b037.

py/selenium/webdriver/remote/webdriver.py

@@ -455,7 +455,7 @@ def page_source(self):
         :Usage:
             driver.page_source
         """
-        return self.execute_script("return document.documentElement.outerHTML;")
+        return self.execute(Command.GET_PAGE_SOURCE)['value']
 
     def close(self):
         """