py: Fixing Python 2 incompatibility. Fixes issue 8274

Author: barancev

Diff for: py/selenium/webdriver/firefox/firefox_profile.py

@@ -27,11 +27,14 @@
 
 try:
     from cStringIO import StringIO as BytesIO
-    bytes = str
-    str = basestring
 except ImportError:
     from io import BytesIO
 
+try:
+    basestring
+except NameError:  # Python 3.x
+    basestring = str
+
 from xml.dom import minidom
 from selenium.webdriver.common.proxy import ProxyType
 from selenium.common.exceptions import WebDriverException