novncproxy fails to establish a VNC connection, if a reverse DNS look up times out

[Roman Podoliaka]

If DNS is configured on a node in a way, so that reverse DNS look ups
time out, noVNC will fail to connect to an instance with 'Connect
timeout' error.

The reverse DNS look up is done implicitly in BaseHTTPRequestHandler
(part of standard library), when logging a request. It's not
configurable, so the only way to disable it is to override the method
of the base class (https://github.com/python/cpython/blob/2.6/Lib/BaseHTTPServer.py#L487).

This is only true for the standard http server (used for novncproxy),
as the eventlet implementation (used for xvpvncproxy) seems to use
plain IP addresses without any reverse DNS look ups.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/156196

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/156196
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=c0f773a616fb48bf699539c5ac18bd9c55a540c9
Submitter: Jenkins
Branch: master

commit c0f773a616fb48bf699539c5ac18bd9c55a540c9
Author: Roman Podoliaka <email address hidden>
Date: Mon Feb 16 11:55:07 2015 +0200

    Fix VNC access, when reverse DNS lookups fail

    If DNS is configured on a node in a way, so that reverse DNS look ups
    time out, noVNC will fail to connect to an instance with 'Connect
    timeout' error.

    The reverse DNS look up is done implicitly in BaseHTTPRequestHandler
    (part of standard library), when logging a request. It's not
    configurable, so the only way to disable it is to override the method
    of the base class.

    This is only true for the standard http server (used for novncproxy),
    as the eventlet implementation (used for xvpvncproxy) seems to use
    plain IP addresses without any reverse DNS look ups.

    Closes-Bug: #1422315

    Change-Id: I8b922de49134eda4d753a8e906b0de55203877d3