PEP8 python-novaclient cleanup

[Zhongyue Luo]

The None, True, and False values are singletons.

All variable *comparisons* to singletons should use 'is' or 'is not'.
All variable *evaluations* to boolean should use 'if' or 'if not'.
All Object type comparisons should use isinstance() instead of comparing types directly

[Zhongyue Luo (zyluo)]

https://review.openstack.org/#change,2772

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/2772
Committed: http://github.com/openstack/python-novaclient/commit/4ff27703d077fc83bb715060a774faf4a15e9736
Submitter: Jenkins
Branch: master

commit 4ff27703d077fc83bb715060a774faf4a15e9736
Author: lzyeval <email address hidden>
Date: Wed Jan 4 09:54:39 2012 +0800

    PEP8 python-novaclient cleanup

    Fixes bug #911552

    The None, True, and False values are singletons.

    All variable *comparisons* to singletons should use 'is' or 'is not'.
    All variable *evaluations* to boolean should use 'if' or 'if not'.
    All Object type comparisons should use isinstance()
    instead of comparing types directly

    Change-Id: Ia5571e58e2662c652f0e996d8c1a1acb4531623d