Comment 4 for bug 1504971

The fix (for now) is to adjust our bug 1372767 fix to handle twisted.web.client having either _URI or URI as a class. Ultimately, it means that we deal with the name change in 2 places. See also https://code.launchpad.net/~lamont/maas/bug-1504971/+merge/274290 -- ultimately changed to be similar to the fix in trunk (1.9).

Once bug 1505748 is fixed in every release we support, we can revisit the fix to drop it entirely. That is flagged in the source.