Summary:

Switch over to django's bundled six library.

Review Request #5497 — Created Feb. 18, 2014 and submitted Feb. 18, 2014, 4:03 p.m.

Description

Now that we've moved to Django 1.6, we no longer need to use the copy shipped
in djblets. This changes all the imports.

Testing Done

Ran unit tests.

Issues

Description	From	Last Updated
Should be before the djblets imports.	chipx86	Feb. 18, 2014, 3:56 p.m.
Should swap these.	chipx86	Feb. 18, 2014, 3:56 p.m.
The six import should go before the other utils imports.	chipx86	Feb. 18, 2014, 3:57 p.m.

reviewboard/hostingsvcs/github.py (Diff revision 1)
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```
Should be before the djblets imports.
```
reviewboard/scmtools/core.py (Diff revision 1)
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```
Should swap these.
```

reviewboard/scmtools/svn/pysvn.py (Diff revision 1)

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The six import should go before the other utils imports.

-	977067e7de635020dcb1a8035abc2d01b7fa4202
+	b801e2e2fa210fdc7dacca7e84c921a38f607d68

Revision 2 (+140 -143)

	reviewboard/accounts/pages.py
	reviewboard/accounts/forms/pages.py
	reviewboard/admin/forms.py
	reviewboard/admin/security_checks.py
	reviewboard/admin/widgets.py
	reviewboard/admin/management/commands/loaddb.py
	reviewboard/cmdline/rbsite.py
	reviewboard/datagrids/columns.py
	98 more

Ship it!

Pushed to master (829daa0).