Open Stack

Hi, I'd like you to take a look at this patch for potential
SecurityImpact.
https://review.openstack.org/87475

Log:
commit bebe906ee7ddcc8785c927b559c930d62e972cbb
Author: Brian Cline <bcline at softlayer.com>
Date:   Tue Apr 15 02:10:28 2014 -0500

    Uses None instead of mutables for function param defaults
    
    Addressing bug 1307878, changes use of mutable lists and dicts as
    default arguments and defaults them within the function. Otherwise,
    those defaults can be unexpectedly persisted with the function between
    invocations and erupt into mass hysteria on the streets.
    
    To my knowledge there aren't known cases of the current use causing
    specific issues, but needs addressing (even stylistically) to avoid
    problems in the future -- ones that may crop up as extremely subtle or
    intermittent bugs...or worse, security vulnerabilities.
    
    In Glance's case there are ACL-related methods using this, so
    although I haven't confirmed one way or the other yet, I've marked it
    with SecurityImpact so that a more knowledgeable set of eyes can
    review it in this context as well.
    
    Closes-Bug: #1307878
    SecurityImpact
    
    Change-Id: Ic17c330eff701ff63701c0029b26db7093a1d73d