Correct the naming because this takes a zip file content as argument, so
it expects bytes not string

_resultForDoCleanups no longer exists on python3, getting the status
of a test in teardown is very different accross python versions ( see
https://stackoverflow.com/q/4414234 ) and just executing this code when
the test failed only has the problem that a test method may count as
two failures or errors, which is after all not a big problem.

This reverts commit d4ab7bb521cc3b75a0d9760dfb83314c38e37767.