Fix json/simplejson handling

[dustin]

 http://lists.debian.org/debian-python/2010/02/msg00016.html

Hello everyone,
It seems like python-json should either be renamed of deprecated.

Meanwhile, all the Python application and modules that use JSON should
be careful when importing the json module. Here's how I do it. (see the
code extract below)

# JSON im# JSON import:
try:
    import json # python 2.6
except ImportError:
    import simplejson as json # python 2.4 to 2.5
try:
    _tmp = json.loads
except AttributeError:
    import warnings
    import sys
    warnings.warn("Use simplejson, not the old json module.")
    sys.modules.pop('json') # get rid of the bad json module
    import simplejson as json

[Dustin J. Mitchell]

Be very careful in how JSON support is imported

And only do it once, in buildbot.util. Fixes #717

Changeset: 161d7fcdccb58b2bae06969912dedf4956978007

[Dustin J. Mitchell]

Be very careful in how JSON support is imported

And only do it once, in buildbot.util. Fixes #717

Changeset: 161d7fcdccb58b2bae06969912dedf4956978007