[py] Fixed improper usage of super in exceptions module

Signed-off-by: Luke Inman-Semerau <[email protected]>

Author: isaulv

py/selenium/common/exceptions.py

@@ -130,7 +130,7 @@ def __init__(self, msg=None, screen=None, stacktrace=None, alert_text=None):
         self.alert_text = alert_text
 
     def __str__(self):
-        return "Alert Text: %s\n%s" % (self.alert_text, str(super(WebDriverException, self)))
+        return "Alert Text: %s\n%s" % (self.alert_text, super(UnexpectedAlertPresentException, self).__str__())
 
 class NoAlertPresentException(WebDriverException):
     """