[Merge] lp:~mterry/auto-upgrade-testing/str-buffer into lp:auto-upgrade-testing

[Michael Terry]

Updated to use the mode="w+" method, which is certainly cleaner.  Thanks, Colin!

This branch is ready to be re-reviewed.
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https://code.launchpad.net/~mterry/auto-upgrade-testing/str-buffer/+merge/113780
Your team Auto Upgrade Testing Developers is requested to review the proposed merge of lp:~mterry/auto-upgrade-testing/str-buffer into lp:auto-upgrade-testing.